CN116273134A - Transition metal-carbon-based catalyst and preparation method and application thereof - Google Patents
Transition metal-carbon-based catalyst and preparation method and application thereof Download PDFInfo
- Publication number
- CN116273134A CN116273134A CN202310552142.8A CN202310552142A CN116273134A CN 116273134 A CN116273134 A CN 116273134A CN 202310552142 A CN202310552142 A CN 202310552142A CN 116273134 A CN116273134 A CN 116273134A
- Authority
- CN
- China
- Prior art keywords
- carbon
- transition metal
- doped
- nitrogen
- catalyst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 239
- 239000003054 catalyst Substances 0.000 title claims abstract description 171
- 230000007704 transition Effects 0.000 title claims abstract description 121
- 238000002360 preparation method Methods 0.000 title claims abstract description 39
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 123
- 238000006243 chemical reaction Methods 0.000 claims abstract description 87
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 76
- 239000007789 gas Substances 0.000 claims abstract description 76
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 67
- 150000003624 transition metals Chemical class 0.000 claims abstract description 53
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 38
- 230000007547 defect Effects 0.000 claims abstract description 21
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 16
- 239000011574 phosphorus Substances 0.000 claims abstract description 16
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052796 boron Inorganic materials 0.000 claims abstract description 15
- 238000010438 heat treatment Methods 0.000 claims description 62
- 239000012018 catalyst precursor Substances 0.000 claims description 40
- 229910052739 hydrogen Inorganic materials 0.000 claims description 38
- 239000001257 hydrogen Substances 0.000 claims description 36
- 239000002243 precursor Substances 0.000 claims description 36
- 238000000034 method Methods 0.000 claims description 32
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 27
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 26
- 229910052751 metal Inorganic materials 0.000 claims description 20
- 239000002184 metal Substances 0.000 claims description 20
- 238000002156 mixing Methods 0.000 claims description 19
- 229910021389 graphene Inorganic materials 0.000 claims description 18
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 13
- 230000008569 process Effects 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 11
- 238000005406 washing Methods 0.000 claims description 11
- 239000002028 Biomass Substances 0.000 claims description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- 239000012190 activator Substances 0.000 claims description 9
- 229910052783 alkali metal Inorganic materials 0.000 claims description 9
- 150000001340 alkali metals Chemical class 0.000 claims description 9
- 150000002431 hydrogen Chemical class 0.000 claims description 9
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 8
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 7
- 239000001569 carbon dioxide Substances 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 239000011733 molybdenum Substances 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 6
- 238000001354 calcination Methods 0.000 claims description 6
- 239000004202 carbamide Substances 0.000 claims description 6
- 229920005610 lignin Polymers 0.000 claims description 6
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 239000011651 chromium Substances 0.000 claims description 4
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 4
- -1 transition metal carbides Chemical class 0.000 claims description 4
- 239000010937 tungsten Substances 0.000 claims description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 229920000877 Melamine resin Polymers 0.000 claims description 3
- 239000001913 cellulose Substances 0.000 claims description 3
- 229920002678 cellulose Polymers 0.000 claims description 3
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims description 3
- 239000011261 inert gas Substances 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 230000003197 catalytic effect Effects 0.000 abstract description 39
- 230000000052 comparative effect Effects 0.000 description 22
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 20
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 15
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 14
- 230000009286 beneficial effect Effects 0.000 description 9
- 238000011065 in-situ storage Methods 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical compound [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 8
- 239000000377 silicon dioxide Substances 0.000 description 8
- 229910052786 argon Inorganic materials 0.000 description 7
- 230000008901 benefit Effects 0.000 description 7
- 238000005984 hydrogenation reaction Methods 0.000 description 7
- 229910000510 noble metal Inorganic materials 0.000 description 7
- 229910004298 SiO 2 Inorganic materials 0.000 description 6
- 230000004913 activation Effects 0.000 description 6
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 235000012239 silicon dioxide Nutrition 0.000 description 5
- 239000012494 Quartz wool Substances 0.000 description 4
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- 238000005054 agglomeration Methods 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 125000004429 atom Chemical group 0.000 description 4
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000000197 pyrolysis Methods 0.000 description 4
- 239000010453 quartz Substances 0.000 description 4
- 239000004480 active ingredient Substances 0.000 description 3
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 description 3
- 235000018660 ammonium molybdate Nutrition 0.000 description 3
- 239000011609 ammonium molybdate Substances 0.000 description 3
- 229940010552 ammonium molybdate Drugs 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 3
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 3
- 238000000192 extended X-ray absorption fine structure spectroscopy Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- QIJNJJZPYXGIQM-UHFFFAOYSA-N 1lambda4,2lambda4-dimolybdacyclopropa-1,2,3-triene Chemical compound [Mo]=C=[Mo] QIJNJJZPYXGIQM-UHFFFAOYSA-N 0.000 description 2
- YLZOPXRUQYQQID-UHFFFAOYSA-N 3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-1-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]propan-1-one Chemical compound N1N=NC=2CN(CCC=21)CCC(=O)N1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F YLZOPXRUQYQQID-UHFFFAOYSA-N 0.000 description 2
- 229910039444 MoC Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- GPBUGPUPKAGMDK-UHFFFAOYSA-N azanylidynemolybdenum Chemical compound [Mo]#N GPBUGPUPKAGMDK-UHFFFAOYSA-N 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- GVHCUJZTWMCYJM-UHFFFAOYSA-N chromium(3+);trinitrate;nonahydrate Chemical compound O.O.O.O.O.O.O.O.O.[Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O GVHCUJZTWMCYJM-UHFFFAOYSA-N 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 2
- 230000009849 deactivation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 238000011066 ex-situ storage Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 230000002779 inactivation Effects 0.000 description 2
- 238000011068 loading method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 238000013112 stability test Methods 0.000 description 2
- 230000005469 synchrotron radiation Effects 0.000 description 2
- OHVLMTFVQDZYHP-UHFFFAOYSA-N 1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)-2-[4-[2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidin-5-yl]piperazin-1-yl]ethanone Chemical compound N1N=NC=2CN(CCC=21)C(CN1CCN(CC1)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)=O OHVLMTFVQDZYHP-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910002837 PtCo Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000012378 ammonium molybdate tetrahydrate Substances 0.000 description 1
- ZRIUUUJAJJNDSS-UHFFFAOYSA-N ammonium phosphates Chemical class [NH4+].[NH4+].[NH4+].[O-]P([O-])([O-])=O ZRIUUUJAJJNDSS-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- FIXLYHHVMHXSCP-UHFFFAOYSA-H azane;dihydroxy(dioxo)molybdenum;trioxomolybdenum;tetrahydrate Chemical compound N.N.N.N.N.N.O.O.O.O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O=[Mo](=O)=O.O[Mo](O)(=O)=O.O[Mo](O)(=O)=O.O[Mo](O)(=O)=O FIXLYHHVMHXSCP-UHFFFAOYSA-H 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- QGUAJWGNOXCYJF-UHFFFAOYSA-N cobalt dinitrate hexahydrate Chemical compound O.O.O.O.O.O.[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O QGUAJWGNOXCYJF-UHFFFAOYSA-N 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- SZQUEWJRBJDHSM-UHFFFAOYSA-N iron(3+);trinitrate;nonahydrate Chemical compound O.O.O.O.O.O.O.O.O.[Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O SZQUEWJRBJDHSM-UHFFFAOYSA-N 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- AOPCKOPZYFFEDA-UHFFFAOYSA-N nickel(2+);dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O AOPCKOPZYFFEDA-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 238000010606 normalization Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/24—Nitrogen compounds
-
- B01J35/40—
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/40—Carbon monoxide
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K3/00—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide
- C10K3/02—Modifying the chemical composition of combustible gases containing carbon monoxide to produce an improved fuel, e.g. one of different calorific value, which may be free from carbon monoxide by catalytic treatment
- C10K3/026—Increasing the carbon monoxide content, e.g. reverse water-gas shift [RWGS]
Abstract
The invention relates to a transition metal-carbon-based catalyst, a preparation method and application thereof. The transition metal-carbon-based catalyst comprises a doped carbon-based carrier and an active component supported on the doped carbon-based carrier; the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron, the active component comprises nanoclusters formed by non-noble transition metal carbide, and the carbon-based carrier doped with the nitrogen, phosphorus and boron can enable the active component to have non-stoichiometric defects. The transition metal-carbon based catalyst has good catalytic activity, high selectivity and good stability, and can be applied to the reverse water gas shift reaction.
Description
Technical Field
The invention relates to the field of reverse water-gas shift reaction, in particular to a transition metal-carbon-based catalyst, a preparation method and application thereof.
Background
The reverse water gas shift reaction (rWGS) is CO 2 An effective way of recycling the CO 2 By H 2 Direct reduction to CO and H 2 O, CO and H 2 The composition of the synthesis gas can be directly used as fuel, and can also be used as raw materials for producing high-grade synthetic fuel and various chemicals.
Noble metal-based catalysts facilitate CO 2 Activation and control of hydrogenation processes has been widely used in a variety of hydrogenation reactions including reverse water vapor shift. For example, researchers have prepared a Pt-based composite catalyst for catalyzing reverse hydro-shift reactions with CO yields of 2678mol at 300 ℃ CO /mol Pt And/h. In addition, researchers synthesize Pd single-atom catalyst Pd1@FeOX, and the CO yield on the surface of the catalyst reaches 42mmol co The selectivity of CO reaches 98 percent per g/h. Another researcher synthesizes a noble metal catalyst PtCo/CeO 2 Realize CO 2 Reverse water-gas shift reaction at 300 deg.C, CO 2 The conversion was 6.6%, the CO selectivity was 82.0%, the reaction conditions were a hydrocarbon ratio of 1:3, and the mass space velocity (WHSV) was 36000mL/g/h.
For the reverse water gas shift reaction, although the noble metal-based catalyst has superior catalytic performance to the non-noble metal-based catalyst, the high cost is unfavorable for large-scale industrial production and application. The activity of the non-noble metal catalyst for the reverse water-gas shift reaction is uneven, the selectivity is also greatly different, and particularly, some catalysts are seriously deactivated after the reaction, so that the stable state is difficult to maintain.
Disclosure of Invention
Based on this, it is necessary to provide a non-noble transition metal-based transition metal-carbon-based catalyst having good catalytic activity, high CO selectivity and good stability, and a method for preparing the same.
In addition, it is necessary to provide an application of the transition metal-carbon based catalyst.
A transition metal-carbon based catalyst comprising: a doped carbon-based carrier and an active component supported on the doped carbon-based carrier;
the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron, and the active component comprises nanoclusters formed from non-noble transition metal carbides, and has non-stoichiometric defects.
In some of these embodiments, the active ingredient meets at least one of the following conditions:
(1) In the transition metal-carbon-based catalyst, the mass percentage of non-noble transition metal elements is 10% -70%;
(2) The non-noble transition metal comprises any one or more of molybdenum, tungsten, chromium, cobalt, nickel, iron and copper;
(3) The particle size of the active component is 3 nm-10 nm.
In some of these embodiments, the doped carbon-based support meets at least one of the following conditions:
(1) The doped carbon-based carrier comprises any one or more of nitrogen-doped biochar and nitrogen-doped graphene;
(2) The mass percentage of doping elements in the doped carbon-based carrier is 5% -20%;
(3) The particle size of the doped carbon-based carrier is 2-10 mu m, and the specific surface area is 200-2000 mu m/g.
A method for preparing a transition metal-carbon-based catalyst, wherein the transition metal-carbon-based catalyst is the transition metal-carbon-based catalyst, and the method comprises the following steps:
obtaining a doped carbon-based carrier, wherein doping elements in the doped carbon-based carrier comprise any one or more of nitrogen, phosphorus and boron;
mixing the doped carbon-based carrier with a non-noble transition metal precursor, and roasting in an inert atmosphere to prepare a catalyst precursor;
performing heat treatment on the catalyst precursor in a reducing atmosphere to prepare the transition metal-carbon-based catalyst, wherein the reducing atmosphere comprises a carbon-containing gas and a reducing gas, or the reducing atmosphere comprises a nitrogen-containing gas and a reducing gas, or the reducing atmosphere comprises an inert gas and a reducing gas, or the reducing atmosphere comprises sublimed sulfur or hydrogen sulfide; or alternatively, the process may be performed,
the preparation method comprises the following steps:
obtaining a doped carbon-based carrier, wherein doping elements in the doped carbon-based carrier comprise any one or more of nitrogen, phosphorus and boron;
Mixing the doped carbon-based carrier with a non-noble transition metal precursor and phosphide, and roasting in an inert atmosphere to prepare a catalyst precursor;
and carrying out heat treatment on the catalyst precursor under the action of reducing gas to prepare the transition metal-carbon-based catalyst.
In some of these embodiments, the step of mixing the doped carbon-based support with a non-noble transition metal precursor, and calcining under an inert atmosphere satisfies at least one of the following conditions:
(1) The mass ratio of the doped carbon-based carrier to the non-noble transition metal precursor is 1 (0.2-1.9);
(2) The step of mixing the doped carbon-based support with a non-noble transition metal precursor and calcining under an inert atmosphere comprises: mixing and stirring the non-noble transition metal precursor, the doped carbon-based carrier and water for 12-48 hours, removing water, drying, and roasting at 500-900 ℃ for 1-4 hours in an inert atmosphere, wherein the non-noble transition metal precursor comprises water-soluble metal salt.
In some embodiments, the reducing atmosphere comprises methane and hydrogen, the volume ratio of methane to hydrogen is 1 (2-5), and the heat treatment comprises: heating to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours; or alternatively, the process may be performed,
The reducing atmosphere comprises nitrogen and hydrogen, the volume ratio of the nitrogen to the hydrogen is (0.5-3) 1, and the heat treatment comprises: heating to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours.
In some of these embodiments, the step of preparing the doped carbon-based support comprises: mixing a biomass carbon source, a doping raw material and an alkali metal activator, pyrolyzing for 1-4 hours at 600-900 ℃ in an inert atmosphere, then carrying out acid washing, water washing and drying to prepare the doped carbon-based carrier, wherein the mass ratio of the biomass carbon source to the doping raw material to the alkali metal activator is (0.5-1): (2-5): (1-3), and the doping raw material comprises any one or more of a nitrogen source, a phosphorus source and a boron source.
In some of these embodiments, the step of preparing the doped carbon-based carrier satisfies at least one of the following conditions:
(1) The biomass carbon source comprises any one or more of lignin and cellulose;
(2) The doping raw materials comprise any one or more of urea, dicyandiamide, melamine and ammonia gas;
(3) The alkali metal activator comprises NaHCO 3 Any one or more of KOH and NaOH.
The use of a transition metal-carbon based catalyst as described above in a reverse water vapor shift reaction.
In some of these embodiments, the reverse water vapor shift reaction satisfies at least one of the following conditions:
(1) In the reverse water-gas shift reaction, the volume ratio of carbon dioxide to hydrogen is 1 (2-8);
(2) The temperature of the reverse water-gas shift reaction is 300-500 ℃;
(3) In the reverse water-gas shift reaction, the mass airspeed is 16000mL/g/h to 800000mL/g/h.
The transition metal-carbon-based catalyst comprises a doped carbon-based carrier and an active component loaded on the doped carbon-based carrier, wherein the doped carbon-based carrier is beneficial to improving non-stoichiometric defects in non-noble transition metal carbide nanoclusters, and CO is greatly improved through abundant non-stoichiometric defect reaction active sites 2 The activation and selective hydrogenation efficiency still have higher catalytic activity and CO selectivity under the reaction conditions of lower temperature range and high hydrogen-carbon ratio. In addition, the doped carbon-based carrier is beneficial to fixing and dispersing active components, and avoids agglomeration and inactivation of the active components, so that the transition metal-carbon-based catalyst has good stability under the reverse water-gas shift reaction condition, and can maintain stable catalytic activity for a long time.
Drawings
FIG. 1 is a schematic illustration of example 1Mo produced 2 C@NGn catalyst and Mo prepared in example 2 2 Stability test results of the C@NBio catalyst under rWGS reaction conditions;
FIG. 2 is a graph identifying active components in transition metal-carbon based catalysts prepared in various examples and comparative examples by an ex situ XRD test;
FIG. 3 shows the Mo prepared in example 1 by in situ XRD testing 2 Active components are formed in the preparation process of the C@NGn, and the stability of the active components is respectively under the reaction and reduction conditions;
FIG. 4 is a graph comparing the performance of transition metal-carbon based catalysts prepared in various examples and comparative examples;
FIG. 5 is Mo prepared in example 1 2 The catalytic performance of the C@NGn catalyst is compared with that of a catalyst prepared conventionally;
FIG. 6 is Mo prepared in example 1 2 Normalized rate of the C@NGn catalyst at different temperatures;
FIG. 7 is a diagram of Mo prepared in example 1 2 C@NGn catalyst and Mo prepared in comparative example 1 2 C@SiO 2 Comparison of the performance of the catalyst to catalyze rWGS reactions;
FIG. 8 is Mo obtained in example 1 2 Comparing the catalytic performances of rWGS reaction of the C@NGn catalyst under different hydrogen-carbon ratios;
FIG. 9 is a diagram of Mo prepared in example 1 2 HAADF TEM and EDS element scanning images of the C@NGn catalyst;
FIG. 10 is a comparison of catalytic performance of the transition metal-carbon based catalysts prepared in example 1, example 7 and example 8;
FIG. 11 is a comparison of catalytic performance of the transition metal-carbon based catalysts prepared in example 1, example 9 and example 10;
FIG. 12 is a comparison of catalytic performance of the transition metal-carbon based catalysts prepared in example 2 and example 3.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to specific embodiments that are now described. Preferred embodiments of the invention are given in the detailed description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Unless otherwise indicated or contradicted, terms or phrases used in the present invention have the following meanings:
in the present invention, "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature.
In the description of the present invention, the meaning of "at least one" means one, two, three, etc., unless explicitly defined otherwise.
In the present invention, "one or more" means any one, any two or more of the listed items. Wherein "several" means any two or more.
In the present invention, the percentage concentrations referred to refer to the final concentrations unless otherwise specified. The final concentration refers to the ratio of the additive component in the system after the component is added.
The words "preferably," "more preferably," and the like in the present invention refer to embodiments of the invention that may provide certain benefits in some instances. However, other embodiments may be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.
When a range of values is disclosed in the present invention, the range is considered to be continuous and includes the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range description features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein.
In the invention, the technical characteristics described in an open mode comprise a closed technical scheme composed of the listed characteristics and also comprise an open technical scheme comprising the listed characteristics.
The terms "comprising" and "having" and any variations thereof in embodiments of the present invention are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed steps or elements but may alternatively include other steps or elements not listed or inherent to such process, method, article, or apparatus.
Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the described embodiments of the invention may be combined with other embodiments.
The inventor finds in experiments that compared with pure metal catalysts, metal carbides have better catalytic activity for rWGS reaction, however, the catalysts have uneven activity for reverse water-gas shift reaction, have larger difference in selectivity, and particularly, some catalysts are seriously deactivated after reaction, so that the stability state is difficult to maintain. Based on the above, the invention provides a transition metal-carbon-based catalyst with good catalytic activity, high selectivity and good stability and a preparation method thereof.
A first aspect of the present invention provides a transition metal-carbon based catalyst comprising a doped carbon-based support and an active component supported on the doped carbon-based support;
the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron, the active component comprises nanoclusters formed from non-noble transition metal carbides, and the active component has non-stoichiometric defects.
The non-stoichiometric defect refers to a defect generated by deviation of positive and negative ion compositions of some compounds from normal stoichiometry due to the influence of external conditions. In this embodiment, the first neighbor metal coordination of the central atom of the active component in the transition metal-carbon based catalyst is significantly reduced, while the non-metal coordination is significantly increased, compared to the unsupported active component, demonstrating the abundance of non-stoichiometric defective active centers due to the doped carbon-based support loading.
In some embodiments, the mass percentage of non-noble transition metal elements in the transition metal-carbon based catalyst is 10% -70%. For example, the mass percent of the non-noble transition metal element may be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or any two of these values. Preferably, the mass percentage of the non-noble transition metal element is 20% -70%. More preferably, the mass percentage of the non-noble transition metal element is 45% -55%.
In some of these embodiments, the non-noble transition metal includes, but is not limited to, any one or more of molybdenum, tungsten, chromium, cobalt, nickel, iron, copper. Preferably, the non-noble transition metal comprises any one or more of molybdenum and tungsten. More preferably, the non-noble transition metal comprises molybdenum.
In some of these embodiments, the active ingredient has the formula M m C, M is non-transition metal, M is the stoichiometric ratio of non-noble transition metal, and M is 0.9-2.
In some of these embodiments, the particle size of the active component is 3nm to 10nm. For example, the particle size of the active component may be, but is not limited to, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm or a range consisting of any two of these values.
In some embodiments, the doped carbon-based carrier comprises 5% -20% of the doping element by mass. For example, the mass percent of doping element may be, but is not limited to, 5%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20% or a range consisting of any two of these values. Too low a mass percentage of doping elements will cause the carrier particle size to become large, and too high a mass percentage will affect the carrier structure. The carbon-based carrier is doped, so that the active components are fixed and dispersed, the agglomeration and deactivation of the active components are avoided, the transition metal-carbon-based catalyst has good stability under the reverse water-gas shift reaction condition, and the stable catalytic activity can be maintained for a long time. If an undoped carbon-based carrier is directly adopted, active components are easy to agglomerate and deactivate at high temperature, so that the catalytic activity is affected.
In some embodiments, the doped carbon-based carrier comprises any one or more of nitrogen-doped biochar and nitrogen-doped graphene.
In some embodiments, the doped carbon-based carrier has a particle size of 2 μm to 10 μm and a specific surface area of 200 m/g to 2000 m/g.
In some of these embodiments, the doped carbon-based carrier comprises nitrogen-doped biochar. The preparation method of the nitrogen-doped biochar comprises the following steps: and mixing a biomass carbon source, a nitrogen source and an alkali metal activator, pyrolyzing for 1-4 hours at 600-900 ℃ in an inert atmosphere, and then carrying out acid washing, water washing and drying to prepare the nitrogen-doped biochar.
In some of these embodiments, the biomass carbon source includes, but is not limited to, any one or more of lignin and cellulose. The nitrogen source includes, but is not limited to, any one or more of urea, dicyandiamide, melamine and ammonia. Alkali metal activators include, but are not limited to, naHCO 3 Any one or more of KOH and NaOH.
In some embodiments, the mass ratio of the biomass carbon source to the nitrogen source to the alkali metal activator is (0.5-1): 2-5): 1-3. Further, the mass ratio of lignin, urea and sodium bicarbonate is (0.5-1): (2-5): (1-3).
In some embodiments, the rate of temperature increase is 3 ℃/min to 20 ℃/min. For example, the heating rate may be, but is not limited to, 3 ℃/min, 4 ℃/min, 5 ℃/min, 6 ℃/min, 8 ℃/min, 10 ℃/min, 12 ℃/min, 14 ℃/min, 15 ℃/min, 16 ℃/min, 18 ℃/min, 20 ℃/min, or a range of any two of these values.
In some of these embodiments, the pyrolysis temperature may be, but is not limited to, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, or a range consisting of any two of these values. The pyrolysis time may be, but is not limited to, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, or a range consisting of any two of these values.
In some of these embodiments, the step of pickling may be, but is not limited to, rinsing with nitric acid. The acid washing is followed by water washing to make the pH of the solution neutral.
In some embodiments, the drying step is performed at a temperature of 50-100 ℃ for a time of 12-48 hours. Alternatively, the drying temperature may be, but is not limited to, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, or a range consisting of any two of these values. The drying time may be, but is not limited to, 12h, 18h, 24h, 30h, 36h, 42h, 48h or a range of any two of these values.
Specifically, in one embodiment, the preparation steps of the nitrogen-doped biochar include: mixing lignin, urea and sodium bicarbonate in a mass ratio of (0.5-1): (2-5): (1-3), heating to 600-900 ℃ at a speed of 3-20 ℃/min under an inert atmosphere, pyrolyzing at 600-900 ℃ for 1-4 hours, then washing with acid, washing with water until the pH of the solution is neutral, and then drying at 50-100 ℃ for 12-48 hours to prepare the nitrogen-doped biochar.
Further, the particle size of the nitrogen-doped biochar is 2-10 mu m, the specific surface area is 200m per gram-700 m per gram, and the pore diameter is 0.1-5 nm. Nanoclusters formed from non-noble transition metal carbides are supported in the pore structure of the nitrogen-doped biochar.
It can be understood that the doped carbon-based carrier can also be phosphorus doped biochar or boron doped biochar, and in the preparation process, a phosphorus source and a boron source are used for replacing the nitrogen source, so that the description is omitted.
In other embodiments, the doped carbon-based carrier comprises nitrogen doped graphene. The nitrogen-doped graphene can be obtained directly on the market or synthesized by a conventional method. In some embodiments, the nitrogen-doped graphene has a particle size of 2-10 μm and a specific surface area of 200-2000 m/g. Further, the nitrogen-doped graphene has a single-layer structure, and the thickness of the single layer is 1 nm-3 nm. The transition metal-carbon based catalyst described above has at least the following advantages:
The transition metal-carbon-based catalyst comprises a doped carbon-based carrier and an active ingredient loaded on the doped carbon-based carrier, wherein the doped carbon-based carrier is beneficial to improving non-stoichiometric defects in non-noble transition metal carbide nanoclusters, and CO is greatly improved through abundant non-stoichiometric defect reaction active sites 2 The activation and selective hydrogenation efficiency still have higher catalytic activity and CO selectivity under the reaction conditions of lower temperature range and high hydrogen-carbon ratio. In addition, the doped carbon-based carrier is beneficial to fixing and dispersing active components, and avoids agglomeration and inactivation of the active components, so that the transition metal-carbon-based catalyst has good stability under the reverse water-gas shift reaction condition, and can maintain stable catalytic activity for a long time.
The second aspect of the present invention also provides a method for preparing the transition metal-carbon-based catalyst of the first embodiment, comprising the steps of:
step S110: a doped carbon-based carrier is obtained, wherein the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron.
Specifically, the doped carbon-based support is as previously described. In some of these embodiments, the doped carbon-based carrier comprises any one or more of nitrogen-doped biochar and nitrogen-doped graphene. The preparation steps of the nitrogen-doped biochar are described above and will not be described in detail. The nitrogen-doped graphene can be obtained directly on the market or synthesized by a conventional method.
Step S120: mixing the doped carbon-based carrier with a non-noble transition metal precursor, and roasting in an inert atmosphere to prepare the catalyst precursor.
Wherein the non-noble transition metal precursor comprises a water soluble salt of a non-noble transition metal. In one specific example, the non-noble transition metal precursor includes: chromium nitrate (CrN) 3 O 9 ) Ammonium molybdate ((NH) 4 ) 6 Mo 7 O 24 ) Cobalt nitrate (CoN) 3 O 9 ) Ammonium tungstate ((NH) 4 ) 10 H 2 (W 2 O 7 ) 6 ) Nickel nitrate (NiN) 2 O 6 ) Ferric nitrate (FeN) 3 O 9 ) Copper nitrate (Cu (NO) 3 ) 2 ) Any one or more of the following. Further, the non-noble transition metal precursor may be, but is not limited to being, in the form of a hydrate. For example, the non-noble transition metal precursor includes chromium nitrate nonahydrate (CrN 3 O 9 ·9H 2 O), ammonium molybdate tetrahydrate ((NH) 4 ) 6 Mo 7 O 24 .4H 2 O), cobalt nitrate hexahydrate (CoN) 3 O 9 ·6H 2 O), ammonium tungstate ((NH) 4 ) 10 H 2 (W 2 O 7 ) 6 ) Nickel nitrate hexahydrate (NiN) 2 O 6 ·6H 2 O), ferric nitrate nonahydrate (FeN) 3 O 9 ·9H 2 O), copper nitrate (Cu (NO) 3 ) 2 ·xH 2 O) any one or more of the following.
Preferably, the non-noble transition metal precursor comprises any one or more of ammonium molybdate and ammonium tungstate. More preferably, the non-noble transition metal precursor comprises ammonium molybdate. Experiments prove that the prepared transition metal-carbon-based catalyst has better performance by taking molybdenum as non-noble transition metal.
In some embodiments, the mass ratio of the doped carbon-based carrier to the non-noble transition metal precursor is 1 (0.2-1.9). For example, the mass ratio of doped carbon-based carrier to non-noble transition metal precursor may be, but is not limited to, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.7, 1:1.9, or a range consisting of any two of these values.
In some of these embodiments, step S120 includes: mixing and stirring the non-noble transition metal precursor, the doped carbon-based carrier and water for 12-48 hours, removing water, drying, and finally roasting for 1-4 hours at 500-900 ℃ in an inert atmosphere.
Specifically, in the step of water removal, the temperature is 50-100 ℃. Alternatively, the temperature of the water removal may be, but is not limited to, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, or a range consisting of any two of these values.
Specifically, the baking temperature may be, but is not limited to, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃ or a range composed of any two of these values. The time of calcination may be, but is not limited to, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, or a range consisting of any two of these values.
Step S130: and carrying out heat treatment on the catalyst precursor in a reducing atmosphere to prepare the transition metal-carbon-based catalyst.
Wherein the reducing atmosphere comprises a carbon-containing gas and a reducing gas, or the reducing atmosphere comprises a nitrogen-containing gas and a reducing gas, or the reducing atmosphere comprises an inert gas and a reducing gas, or the reducing atmosphere comprises sublimed sulfur or hydrogen sulfide.
In some embodiments, the heat treatment is performed at a temperature of 700 ℃ to 1000 ℃ for a time of 1h to 4h. Further, the heat treatment includes: heating to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours. Still further, the heat treatment includes: firstly, heating to 300 ℃ at the speed of 3-10 ℃/min, then heating to 700-1000 ℃ at the speed of 2-10 ℃/min, and carrying out heat treatment for 1-4 hours at the temperature of 700-1000 ℃.
In some embodiments, the reducing atmosphere comprises methane and hydrogen, optionally, the volume ratio of methane to hydrogen in the reducing atmosphere is 1 (2-5). For example, the volume ratio of methane to hydrogen may be, but is not limited to, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or a range consisting of any two of these values.
Further, the step of heat-treating the catalyst precursor in a reducing atmosphere includes: and (3) in the mixed gas of methane and hydrogen with the volume ratio of 1 (2-5), carrying out heat treatment on the catalyst precursor for 1-4 h at the temperature of 700-1000 ℃. Further, the catalyst precursor is heated to 300 ℃ at a speed of 3-10 ℃ per minute, and then heated to 700-1000 ℃ at a speed of 2-10 ℃ per minute, and heat treatment is carried out for 1-4 hours.
In other embodiments, the reducing atmosphere comprises nitrogen and hydrogen, optionally, in the reducing atmosphere, the volume ratio of hydrogen to nitrogen is 1 (0.5-3). For example, the volume ratio of hydrogen to nitrogen may be, but is not limited to, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, or a range of any two of these values.
Further, the step of heat-treating the catalyst precursor in a reducing atmosphere includes: and (3) carrying out heat treatment on the catalyst precursor for 1-4 hours at 700-1000 ℃ in a mixed atmosphere of hydrogen and nitrogen with the volume ratio of (0.5-3). Further, the catalyst precursor is heated to 300 ℃ at a speed of 3-10 ℃ per minute, and then heated to 700-1000 ℃ at a speed of 2-10 ℃ per minute, and heat treatment is carried out for 1-4 hours.
In other embodiments, the reducing atmosphere comprises hydrogen and argon. The volume ratio of the hydrogen to the argon is 1 (1-5). For example, the volume ratio of hydrogen to argon may be, but is not limited to, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:4, 1:5, or a range of any two of these values.
In other embodiments, the reducing atmosphere comprises sublimed sulfur or hydrogen sulfide.
Further, the step of heat-treating the catalyst precursor in a reducing atmosphere includes: and carrying out heat treatment on the catalyst precursor for 1-4 hours at 700-1000 ℃ in the presence of sublimed sulfur or hydrogen sulfide. Further, the catalyst precursor is heated to 300 ℃ at a speed of 3-10 ℃ per minute, and then heated to 700-1000 ℃ at a speed of 2-10 ℃ per minute, and heat treatment is carried out for 1-4 hours.
Experiments prove that the active components obtained by heat treatment under the condition of reducing atmosphere are nanoclusters formed by non-noble transition metal carbide.
Preferably, step S130 includes: performing heat treatment on the catalyst precursor in a mixed atmosphere of methane and hydrogen with the volume ratio of (2-5) to prepare the transition metal-carbon-based catalyst, wherein the heat treatment comprises the following steps: and heating the catalyst precursor to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours. Experiments prove that when the reducing atmosphere is carbon-containing gas and reducing gas, the prepared transition metal-carbon-based catalyst has better performance.
The preparation method of the transition metal-carbon-based catalyst has at least the following advantages:
(1) The preparation method of the transition metal-carbon-based catalyst has simple process, and the doped carbon-based carrier structure is beneficial to improving the non-stoichiometric defects (or metal defects) in the non-noble transition metal carbide nanocluster, and greatly improves CO through abundant non-stoichiometric defect reaction active sites 2 The activation and selective hydrogenation efficiency still have higher catalytic activity and CO selectivity under the reaction conditions of lower temperature range and high hydrogen-carbon ratio.
(2) The preparation method of the transition metal-carbon-based catalyst is feasible and low in cost, and is beneficial to mass production.
(3) The preparation method of the transition metal-carbon-based catalyst uses the nitrogen doped biochar as the representative low-cost carbon-based carrier, is an effective solution for effectively dispersing metal active centers, long-acting and stable active sites, constructing metal defects and selectively hydrogenating, and further reduces the cost.
The second aspect of the present invention also provides a method for preparing a transition metal-carbon-based catalyst of the second embodiment, comprising the steps of:
step S210: a doped carbon-based carrier is obtained, wherein the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron.
Specifically, step S210 is the same as step S110 in the preparation method of the transition metal-carbon based catalyst of the first embodiment, and will not be described again.
Step S220: mixing the doped carbon-based carrier with a non-noble transition metal precursor and phosphide, and roasting in an inert atmosphere to prepare the catalyst precursor.
Specifically, the non-noble transition metal precursor is the same as that described above, and will not be described again.
In some of these embodiments, the phosphorus-containing compound includes, but is not limited to, any one or more of ammonium phosphate salts and phosphoric acid.
In some of these embodiments, the mass of phosphide is the same as the mass of the doped carbon-based carrier.
In some of these embodiments, step S220 includes: mixing and stirring the non-noble transition metal precursor, the doped carbon-based carrier, the phosphide and water for 12-48 h, removing water, drying, and finally roasting for 1-4 h at 500-900 ℃ in an inert atmosphere.
Specifically, in the step of water removal, the temperature is 50-100 ℃. Alternatively, the temperature of the water removal may be, but is not limited to, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, or a range consisting of any two of these values.
Specifically, the baking temperature may be, but is not limited to, 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃ or a range composed of any two of these values. The time of calcination may be, but is not limited to, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, or a range consisting of any two of these values.
Step S220: and (3) performing heat treatment on the catalyst precursor under the action of reducing gas to prepare the transition metal-carbon-based catalyst.
In some embodiments, the reducing gas comprises hydrogen, and step S220 comprises: and (3) carrying out heat treatment on the catalyst precursor for 1-4 hours at 700-1000 ℃ in a hydrogen atmosphere. Further, the catalyst precursor is heated to 300 ℃ at a speed of 3-10 ℃ per minute, and then heated to 700-1000 ℃ at a speed of 2-10 ℃ per minute, and heat treatment is carried out for 1-4 hours.
The preparation method of the transition metal-carbon-based catalyst has at least the following advantages:
(1) The preparation method of the transition metal-carbon-based catalyst has simple process and is beneficial to utilizing the doped carbon-based carrier structureThe non-stoichiometric defect (or metal defect) in the non-noble transition metal carbide nanocluster is improved, and the CO is greatly improved through abundant non-stoichiometric defect reaction active sites 2 The activation and selective hydrogenation efficiency still have higher catalytic activity and CO selectivity under the reaction conditions of lower temperature range and high hydrogen-carbon ratio.
(2) The preparation method of the transition metal-carbon-based catalyst is feasible and low in cost, and is beneficial to mass production.
(3) The preparation method of the transition metal-carbon-based catalyst uses the nitrogen doped biochar as the representative low-cost carbon-based carrier, is an effective solution for effectively dispersing metal active centers, long-acting and stable active sites, constructing metal defects and selectively hydrogenating, and further reduces the cost.
The third aspect of the invention also provides the use of a transition metal-carbon based catalyst in a reverse water gas shift reaction.
Specifically, the reverse water vapor shift reaction includes the steps of:
and (3) under the action of a transition metal-carbon-based catalyst, carrying out reverse water-gas shift reaction on the mixed gas of carbon dioxide and hydrogen.
In some embodiments, the volume ratio of carbon dioxide to hydrogen is 1 (2-8). Alternatively, the volume ratio of carbon dioxide to hydrogen may be, but is not limited to, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or a range of any two of these values. Experiments prove that the transition metal-carbon based catalyst has high CO selectivity and higher CO in the hydrogen-carbon ratio range 2 Conversion rate.
In some embodiments, the mixed gas further comprises nitrogen. In a specific example, the mixed gas includes: 5 mL/min-20 mL/min CO 2 、10mL/min~40mL/min H 2 5mL/min to 20mL/min N 2 。
In some embodiments, the temperature of the reverse water vapor shift reaction is 300 ℃ to 500 ℃. The time is 2-50 h. Alternatively, the temperature of the reverse water vapor shift reaction may be, but is not limited to, 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃, or any two of these valuesThe range of which is composed. Experiments prove that the transition metal-carbon based catalyst has high CO selectivity and higher CO in the temperature range 2 Conversion rate. Alternatively, the time of the reverse water vapor shift reaction may be, but is not limited to, 2h, 5h, 10h, 15h, 20h, 25h, 30h, 40h, 50h, or a range consisting of any two of these values.
Further, the temperature rising rate is 5 ℃/min to 20 ℃/min. For example, the heating rate may be, but is not limited to, 5 ℃/min, 8 ℃/min, 10 ℃/min, 12 ℃/min, 14 ℃/min, 15 ℃/min, 16 ℃/min, 18 ℃/min, 20 ℃/min, or a range of any two of these values.
In some embodiments, in the reverse water vapor shift reaction, the mass space velocity (WHSV) is 16000mL/g/h to 800000mL/g/h. For example, the mass space velocity may be, but is not limited to, 16000mL/g/h, 20000mL/g/h, 50000mL/g/h, 80000mL/g/h, 100000mL/g/h, 120000mL/g/h, 140000mL/g/h, 200000mL/g/h, 250000mL/g/h, 280000mL/g/h, 300000mL/g/h, 400000mL/g/h, 500000mL/g/h, 600000mL/g/h, 800000mL/g/h, or a range comprised of any two of these values.
In some of these embodiments, the pressure of the reverse water vapor shift reaction is atmospheric.
Specifically, during the reaction, the concentration of the gaseous product was analyzed with a Flame Ionization Detector (FID) and a gas chromatograph (Agilent 7890B) of a Thermal Conductivity Detector (TCD) to obtain CO 2 Conversion and CO selectivity.
In a specific example, the reverse water vapor shift reaction is performed in an atmospheric flow reactor. Further, 5mg to 80mg of the transition metal-carbon-based catalyst is put into a quartz tube with an inner diameter of 4mm to 10mm, and is fixed by quartz wool.
The use of the above-described transition metal-carbon based catalyst in a reverse water vapor shift reaction has at least the following advantages:
(1) The adoption of the transition metal-carbon-based catalyst for the reverse water-gas shift reaction obviously improves CO in the reverse water-gas shift reaction 2 Conversion rate and CO selectivity, and greatly improves the atomic utilization rate, and simultaneously, the conversion rate and CO selectivity are improved in the reverse water-gas shift reactionUnder the condition and in a harsher reducing atmosphere, the transition metal-carbon-based catalyst has stable catalytic activity.
(2) The reverse water-gas shift reaction uses non-noble transition metal carbide nanoclusters as active components, reduces the cost compared with noble metal-based catalysts, and is easy for large-scale industrial application.
In order to make the objects and advantages of the present invention more apparent, the transition metal-carbon based catalyst and its effects according to the present invention will be described in further detail with reference to the following examples, which are to be construed as merely illustrative, and not limitative of the present invention. The following examples, unless otherwise specified, do not include other components than the unavoidable impurities. The drugs and apparatus used in the examples are all routine choices in the art, unless specifically indicated. The experimental methods without specific conditions noted in the examples were carried out according to conventional conditions, such as those described in the literature, books, or recommended by the manufacturer.
Example 1
The present example provides a transition metal-carbon based catalyst, prepared as follows:
(1) Preparation of nitrogen doped carbon-based supports
Grinding and screening nitrogen doped graphene NGn (the mass percentage of nitrogen element is 5.38 percent, and the layer thickness is 1 nm-3 nm) until the particle size is 2-10 mu m and the specific surface area is 200 m/g for later use.
(2) Preparation of catalyst precursor
Non-noble transition metal precursor (NH) 4 ) 6 Mo 7 O 24 .4H 2 Mixing O and the nitrogen-doped graphene obtained in the step (1) in water, wherein the mass ratio of the non-noble transition metal precursor to the carrier is 1.842:1, and stirring in a shaking table at 25 ℃ for 24 hours. Evaporating at 80deg.C to remove water, drying at 60deg.C for 24 hr, and purifying with 500 deg.C pure N 2 Middle roasting for 2 hours to prepare a catalyst precursor which is marked as MoO 2 @NGn。
(3) Preparation of transition metal-carbon based catalysts
In an atmospheric flow reactor, the10mg of catalyst precursor (MoO) 2 @ NGn) is placed in a quartz tube with an inner diameter of 4mm and fixed with quartz wool, and CH with a volume ratio of 1:4 is introduced 4 /H 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 25mL/min, the temperature is firstly increased to 300 ℃ at the heating rate of 10 ℃/min, then is increased to 700 ℃ at the heating rate of 2 ℃/min, and is stabilized at 700 ℃ for 2 hours, so that the transition metal-carbon-based catalyst of the embodiment is obtained and is marked as Mo 2 C@NGn。
The content of the metal element in the transition metal-carbon based catalyst prepared in example 1 was tested, and the content of Mo element in the transition metal-carbon based catalyst prepared in example 1 was 50% by mass.
Example 2
This example provides a transition metal-carbon based catalyst similar to the preparation step of the transition metal-carbon based catalyst of example 1, except that in step (1), the nitrogen-doped carbon-based carrier is nitrogen-doped biochar, and the preparation steps are as follows: with lignin, urea and NaHCO 3 Raw materials are mixed according to the mass ratio of 1:4:3, heated to 700 ℃ in a graphite crucible at the heating rate of 3 ℃/min and pyrolyzed for 2 hours at 700 ℃. The naturally cooled solid product was then treated with 1M HNO 3 The solution is washed, and then water is added for washing until the pH value of the solution is 7. And drying at 60 ℃ for 24 hours to obtain the nitrogen-doped biochar NBio, wherein the nitrogen-doped biochar contains 10% of nitrogen element by mass percent through testing. The transition metal-carbon based catalyst obtained in this example was designated Mo 2 C@NBio。
Example 3
This example provides a transition metal-carbon based catalyst similar to the preparation step of the transition metal-carbon based catalyst of example 2, except that in step (1), the pyrolysis temperature during the preparation of the nitrogen-doped carbon based support was replaced with 800 ℃ for 700 ℃ in example 2.
Example 4
This example provides a transition metal-carbon-based catalyst, which is similar to the preparation procedure of the transition metal-carbon-based catalyst of example 1, except that in the step (3), the reducing atmosphere is different, theStep (3) of the embodiment is: the catalyst precursor is prepared by using N with the volume ratio of 1:1 2 /H 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 20mL/min, the temperature is firstly increased to 700 ℃ at the heating rate of 10 ℃/min, and then the mixed gas is stabilized at 700 ℃ for 2 hours, so that the transition metal-carbon-based catalyst is prepared.
Example 5
The present example provides a transition metal-carbon-based catalyst similar to the preparation procedure of the transition metal-carbon-based catalyst of example 1, except that in step (3), the reducing atmosphere and the heat treatment are different, and step (3) of the present example is: the catalyst precursor is prepared by using N with the volume ratio of 1:1 2 /H 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 20mL/min, the temperature is raised to 800 ℃ at the heating rate of 10 ℃/min, and then the mixed gas is stabilized at 800 ℃ for 8 hours, so that the transition metal-carbon-based catalyst is prepared.
Example 6
The present embodiment provides a transition metal-carbon-based catalyst similar to the preparation step of the transition metal-carbon-based catalyst of embodiment 1, except that in step (3), the reducing atmosphere is different, and step (3) of the present embodiment is: the catalyst precursor is prepared by Ar/H with the volume ratio of 1:1 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 20mL/min, the temperature is firstly increased to 700 ℃ at the heating rate of 10 ℃/min, and then the mixed gas is stabilized at 700 ℃ for 2 hours, so that the transition metal-carbon-based catalyst is prepared.
Example 7
The present example provides a transition metal-carbon based catalyst similar to the preparation procedure of the transition metal-carbon based catalyst of example 1, except that in step (2), the non-noble transition metal precursor is different from the non-noble transition metal precursor, in the present example, chromium nitrate nonahydrate (CrN 3 O 9 ·9H 2 O); in the step (3), the carbonization pretreatment temperatures were different, and the carbonization pretreatment temperature in this example was 850 ℃.
Example 8
This example provides a transition metal-carbon-based catalyst, similar to the preparation procedure of the transition metal-carbon-based catalyst of example 1, with the difference thatIn step (2), the non-noble transition metal precursor is different, and in this embodiment, the non-noble transition metal precursor is ammonium tungstate (NH) 4 ) 10 H 2 (W 2 O 7 ) 6 。
Example 9
This example provides a transition metal-carbon based catalyst similar to the transition metal-carbon based catalyst of example 1, except that in step (2), the mass ratio of non-noble transition metal precursor to nitrogen doped graphene is 0.47:1. The test shows that the mass percentage of the non-noble transition metal element in the prepared transition metal-carbon-based catalyst is 20%.
Example 10
This example provides a transition metal-carbon based catalyst similar to the transition metal-carbon based catalyst of example 1, except that in step (2), the mass ratio of non-noble transition metal precursor to nitrogen doped graphene is 0.21:1. The test shows that the mass percentage of the non-noble transition metal element in the prepared transition metal-carbon-based catalyst is 10%.
Comparative example 1
The comparative example provides a catalyst similar to the preparation procedure of the transition metal-carbon based catalyst of example 1, except that in step (1), the carrier is replaced with silica, and the silica is ground and sieved to a particle size of 0.125mm to 0.250mm for use.
Comparative example 2
The comparative example provides a catalyst similar to the preparation step of the transition metal-carbon based catalyst of example 1, except that in step (1), the carrier is replaced with silica, and the silica is ground and sieved to a particle size of 0.125mm to 0.250mm for later use; in step (2), the pretreatment process of the catalyst precursor was different, and in comparative example 4, the catalyst precursor was treated with N in a volume ratio of 1:1 2 /H 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 20mL/min, the temperature is firstly increased to 700 ℃ at the heating rate of 10 ℃/min, and then the mixed gas is stabilized at 700 ℃ for 2 hours, so that the catalyst after nitriding treatment is prepared.
Comparative example 3
The comparative example provides a catalyst similar to the preparation step of the transition metal-carbon based catalyst of example 1, except that in step (1), the carrier is replaced with silica, and the silica is ground and sieved to a particle size of 0.125mm to 0.250mm for later use; in step (2), the pretreatment process of the catalyst precursor was different, and in comparative example 3, the catalyst precursor was subjected to Ar/H at a volume ratio of 1:1 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 20mL/min, the temperature is firstly increased to 700 ℃ at the heating rate of 10 ℃/min, and then the mixed gas is stabilized for 2 hours at 700 ℃ to prepare the catalyst.
Comparative example 4
This comparative example provides a catalyst similar to the procedure for the preparation of the transition metal-carbon based catalyst of example 1, except that no loading was performed and the procedure for the preparation of the catalyst of comparative example 4 was as follows:
metal precursor (NH) 4 ) 6 Mo 7 O 24 .4H 2 O was dissolved in water and stirred in a shaker at 25℃for 24 hours. Evaporating at 80deg.C to remove water, drying at 60deg.C for 24 hr, and purifying with 500 deg.C pure N 2 And (3) roasting for 2 hours to prepare the catalyst precursor.
In an atmospheric flow reactor, 10mg of catalyst precursor (MoO 2 ) Putting into a quartz tube with an inner diameter of 4mm, fixing with quartz wool, and introducing CH with a volume ratio of 1:4 4 /H 2 The mixed gas is subjected to in-situ pretreatment, the total flow rate of the mixed gas is 25mL/min, the temperature is firstly increased to 300 ℃ at the heating rate of 10 ℃/min, then is increased to 700 ℃ at the heating rate of 2 ℃/min, and is stabilized at 700 ℃ for 2 hours, so as to prepare the catalyst Mo 2 C。
The following are specific test parts:
the catalyst prepared in each example and comparative example was subjected to a reverse water-gas shift reaction, and in a normal pressure flow reactor, the catalyst was packed in a quartz tube having an inner diameter of 4mm and fixed with quartz wool, and the conditions of the reactor such as temperature, hydrogen-carbon ratio, mass space velocity, etc. were adjusted to carry out the reverse water-gas shift reaction. The concentration of the gaseous product was analyzed using a gas chromatograph (Agilent 7890B) equipped with a Flame Ionization Detector (FID) and a Thermal Conductivity Detector (TCD). The following reverse water-gas shift reaction is carried out for 2 hours, nitrogen is also added into the mixed gas, and the heating rate is 10 ℃/min.
FIG. 1 is Mo prepared in example 1 2 C@NGn catalyst and Mo prepared in example 2 2 Stability test results of the c@nbio catalyst under rWGS reaction conditions. Wherein the reaction condition is that the mass airspeed=140000 mL/g/h, the temperature is 500 ℃, and the mol is that CO2 :mol H2 =1:2, pressure 1bar.
Where CO selectivity refers to the molar amount of CO as a percentage of the molar amount of all products. CO 2 Conversion refers to converted CO 2 Molar mass of CO in the feed gas 2 Percentage of molar amount.
As can be seen from FIG. 1, the two transition metal-carbon based catalysts have comparable catalytic properties, both of which have higher CO 2 The conversion rate and the high Co selectivity are high, and the catalyst has good stability under long-time reaction conditions.
Fig. 2 is a graph identifying active components in transition metal-carbon based catalysts prepared in various examples and comparative examples by an ex situ XRD test. As can be seen from fig. 2, in examples 4 to 6, nitrogen-doped graphene is used as a carrier, and the catalyst precursor is subjected to heat treatment in an atmosphere of nitrogen and hydrogen, so that the obtained transition metal-carbon-based catalyst active component is still molybdenum carbide, but not molybdenum nitride; the active component obtained by heat treatment under an atmosphere of argon and hydrogen is likewise molybdenum carbide. In comparative examples 2 to 3, the catalyst precursor was pretreated with silica as a carrier in an atmosphere of nitrogen and hydrogen, the metal active component obtained was molybdenum nitride, and the active component obtained in an atmosphere of argon and hydrogen was molybdenum.
FIG. 3 shows the Mo prepared in example 1 by in situ XRD testing 2 Active component formation during preparation of c@ngn, and stability under reaction and reduction conditions, respectively. Wherein, the formation of the active component comprises two stages of pretreatment heating and pretreatment constant temperature. The reaction conditions were 500℃containing carbon dioxide and hydrogen. The reduction conditions are hydrogen and argon The gas temperature is 500 ℃, and in fig. 3, the pretreatment temperature is raised, the pretreatment constant temperature, the reaction condition and the reduction condition are sequentially corresponding from bottom to top. As can be seen from fig. 3, the catalyst precursor is MoO during the heat treatment stage 2 Conversion to Mo 2 And C, the active components are not changed under the reaction conditions containing carbon dioxide and hydrogen and the reduction conditions containing hydrogen and argon, so that the catalyst has good stability.
FIG. 4 is a graph showing the comparison of the performance of the catalysts prepared in the examples and comparative examples, under the following test conditions: WHSV=140000 mL/g/h, mol CO2 :mol H2 =1:2. As can be seen from fig. 4: 1) In the catalyst, the carrier is the nitrogen-doped graphene or the nitrogen-doped biochar prepared in the embodiment, and compared with the carrier which is silicon dioxide in the comparative example, the conversion rate of carbon monoxide is obviously improved; 2) The atmosphere in the heat treatment process can influence the performance of the transition metal-carbon-based catalyst, the performance of the transition metal-carbon-based catalyst can be further improved by optimizing the atmosphere in the heat treatment process, and the catalytic performance of the prepared transition metal-carbon-based catalyst is better when the heat treatment is carried out in a carbon-containing atmosphere than when the heat treatment is carried out in a nitrogen-containing atmosphere or in a protective atmosphere and a hydrogen atmosphere; 3) Compared with the nitrogen-doped biochar, the prepared transition metal-carbon-based catalyst has little difference in performance, and the nitrogen-doped biochar has wider raw material sources and lower cost.
Table 1 and FIG. 5 show the Mo prepared in example 1 2 The catalytic performance of the C@NGn catalyst is compared with that of a catalyst prepared conventionally.
TABLE 1
Wherein the normalization rate is the molar quantity of CO which can be generated per gram of catalyst per hour, and can be based on the mass space velocity and CO 2 Volume fraction, CO 2 Conversion and CO selectivity were calculated.
As can be seen from Table 1 and FIG. 5, the above example 1 prepared compared with the conventional noble metal catalyst and the composite catalystThe transition metal-carbon based catalyst has obvious catalytic performance advantage for rWGS reaction, and is mainly characterized by high catalytic reaction rate, low hydrogen-carbon ratio and high CO under the reaction condition of lower temperature 2 Conversion and high CO selectivity.
FIG. 6 is Mo prepared in example 1 2 Normalized CO generation rate of C@NGn catalyst at different temperatures, and reaction conditions are WHSV=140000 mL/g/h, and mol CO2 :mol H2 =1:2。
FIG. 7 is a diagram of Mo prepared in example 1 2 C@NGn catalyst and Mo prepared in comparative example 1 2 C@SiO 2 Comparison of the performance of the catalyst to catalyze rWGS reactions. Wherein, the reaction conditions are as follows: in using Mo 2 Whsv=16000 mL/g/h at c@ngn, mo is used 2 C@SiO 2 When the WHSV is 12000mL/g/h; mol (mol) CO2 :mol H2 =1:2. As can be seen from FIG. 7, mo 2 C@NGn is compared with Mo 2 C@SiO 2 Has better catalytic performance.
FIG. 8 is Mo obtained in example 1 2 Comparison of the catalytic performances of rWGS reactions under different hydrogen-carbon ratios of the catalyst C@NGn. Wherein, the reaction conditions are as follows: whsv= 318000mL/g/h. As can be seen from FIG. 8, CO increases with the hydrogen-to-carbon ratio 2 The conversion rate is obviously improved, and the transition metal-carbon-based catalyst still has high CO selectivity under the condition of high hydrogen-carbon ratio.
FIG. 9 is a diagram of Mo prepared in example 1 2 The elemental composition and metal dispersion of the transition metal-carbon based catalyst can be confirmed from fig. 9 by scanning the HAADF TEM (high angle annular dark field transmission electron microscope) and EDS (energy dispersive x-ray spectroscopy) elemental scans of the c@ngn catalyst.
Fig. 10 is a comparison of catalytic performance of the transition metal-carbon based catalysts prepared in example 1, example 7 and example 8. Wherein the reaction condition is WHSV=140000 mL/g/h, mol CO2 :mol H2 =1:2. As can be seen from fig. 10, the transition metal is Mo, which has better catalytic activity than the metals Cr and W.
FIG. 11 shows the catalytic properties of the transition metal-carbon based catalysts prepared in example 1, example 9 and example 10Can be compared. Wherein, the reaction condition is WHSV=140000 mL/g/h, mol CO2 :mol H2 =1:2. As can be seen from FIG. 11, CO increases with the content of the transition metal element 2 The conversion increases gradually and high CO selectivity is maintained.
FIG. 12 is a comparison of catalytic performance of the transition metal-carbon based catalysts prepared in example 2 and example 3. Wherein Mo is 2 C@Biochar-C700 corresponding to the transition metal-carbon based catalyst prepared in example 2, biochar represents Biochar, mo 2 The C@Biochar-C800 corresponds to the transition metal-carbon based catalyst prepared in example 3, and it can be seen from the graph that the nitrogen-doped biochar prepared at different pyrolysis temperatures has better catalytic performance in the transition metal-carbon based catalyst, and the nitrogen-doped biochar prepared at 700 ℃ has better catalytic performance in the transition metal-carbon based catalyst.
For Mo prepared in example 1 2 C@NGn catalyst and Mo prepared in comparative example 1 2 C@SiO 2 Catalyst and Mo prepared in comparative example 4 2 The catalyst C was subjected to synchrotron radiation extended X-ray absorption fine structure spectroscopy (EXAFS) and the average coordination number of the metal atoms M was calculated to obtain the data shown in Table 2 below. As can be seen from table 2, on the surface of the nitrogen-doped graphene carrier, the first neighboring metal coordination of the central atom is significantly reduced, while the non-metal coordination is significantly increased, demonstrating the rich defect active center generated by the nitrogen-doped graphene carrier. Less loaded and with SiO 2 Catalytic system as support, mo 2 The catalytic performance of the C@NGn is obviously improved, which indicates that the metal active center is a potential source of catalytic activity. The combination of the data shows that the two carbon carrier catalytic systems related by the invention have good catalytic activity, the cost of the nitrogen-doped biochar carrier catalytic system is only 5% of that of the nitrogen-doped graphene catalytic system, a cheaper solution is provided, and the method has wide application prospect.
TABLE 2 calculation of the mean coordination number of the metal atoms M based on the synchrotron radiation extended X-ray absorption Fine Structure Spectrum (EXAFS)
In the above examples, the nitrogen-doped carbon-based carrier is taken as an example, and the phosphorus-doped or boron-doped carbon-based carrier has the same properties as the nitrogen-doped carbon-based carrier, and can also fix and disperse the active components, so as to avoid agglomeration and deactivation of the active components, so that the transition metal-carbon-based catalyst has good stability under the reverse water-gas shift reaction condition, and the doped carbon-based carrier is beneficial to improving the non-stoichiometric defects in the non-noble transition metal carbide nanoclusters compared with the undoped carbon-based carrier, and greatly improves the CO through abundant non-stoichiometric defect reaction active sites 2 The activation and selective hydrogenation efficiency still have higher catalytic activity and CO selectivity under the reaction conditions of lower temperature range and high hydrogen-carbon ratio.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present invention, which facilitate a specific and detailed understanding of the technical solutions of the present invention, but are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. It should be understood that, based on the technical solutions provided by the present invention, those skilled in the art can obtain technical solutions through logical analysis, reasoning or limited experiments, which are all within the protection scope of the appended claims. The scope of the patent is therefore intended to be covered by the appended claims, and the description and drawings may be interpreted as illustrative of the contents of the claims.
Claims (10)
1. A transition metal-carbon based catalyst, comprising: a doped carbon-based carrier and an active component supported on the doped carbon-based carrier;
the doping element in the doped carbon-based carrier comprises any one or more of nitrogen, phosphorus and boron, and the active component comprises nanoclusters formed from non-noble transition metal carbides, and has non-stoichiometric defects.
2. The transition metal-carbon based catalyst according to claim 1, wherein the active component satisfies at least one of the following conditions:
(1) In the transition metal-carbon-based catalyst, the mass percentage of non-noble transition metal elements is 10% -70%;
(2) The non-noble transition metal element comprises any one or more of molybdenum, tungsten, chromium, cobalt, nickel, iron and copper;
(3) The particle size of the active component is 3 nm-10 nm.
3. The transition metal-carbon based catalyst according to claim 1 or 2, wherein the doped carbon-based support meets at least one of the following conditions:
(1) The doped carbon-based carrier comprises any one or more of nitrogen-doped biochar and nitrogen-doped graphene;
(2) The mass percentage of doping elements in the doped carbon-based carrier is 5% -20%;
(3) The particle size of the doped carbon-based carrier is 2-10 mu m, and the specific surface area is 200-2000 mu m/g.
4. A method for preparing a transition metal-carbon-based catalyst, characterized in that the transition metal-carbon-based catalyst is the transition metal-carbon-based catalyst according to any one of claims 1 to 3, comprising the steps of:
obtaining a doped carbon-based carrier, wherein doping elements in the doped carbon-based carrier comprise any one or more of nitrogen, phosphorus and boron;
mixing the doped carbon-based carrier with a non-noble transition metal precursor, and roasting in an inert atmosphere to prepare a catalyst precursor;
performing heat treatment on the catalyst precursor in a reducing atmosphere to prepare the transition metal-carbon-based catalyst, wherein the reducing atmosphere comprises a carbon-containing gas and a reducing gas, or the reducing atmosphere comprises a nitrogen-containing gas and a reducing gas, or the reducing atmosphere comprises an inert gas and a reducing gas, or the reducing atmosphere comprises sublimed sulfur or hydrogen sulfide; or alternatively, the process may be performed,
the preparation method comprises the following steps:
obtaining a doped carbon-based carrier, wherein doping elements in the doped carbon-based carrier comprise any one or more of nitrogen, phosphorus and boron;
Mixing the doped carbon-based carrier with a non-noble transition metal precursor and phosphide, and roasting in an inert atmosphere to prepare a catalyst precursor;
and carrying out heat treatment on the catalyst precursor under the action of reducing gas to prepare the transition metal-carbon-based catalyst.
5. The method of preparing a transition metal-carbon based catalyst according to claim 4, wherein the step of mixing the doped carbon-based support with a non-noble transition metal precursor and calcining under an inert atmosphere satisfies at least one of the following conditions:
(1) The mass ratio of the doped carbon-based carrier to the non-noble transition metal precursor is 1 (0.2-1.9);
(2) The step of mixing the doped carbon-based support with a non-noble transition metal precursor and calcining under an inert atmosphere comprises: mixing and stirring the non-noble transition metal precursor, the doped carbon-based carrier and water for 12-48 hours, removing water, drying, and roasting at 500-900 ℃ for 1-4 hours in an inert atmosphere, wherein the non-noble transition metal precursor comprises water-soluble metal salt.
6. The method for preparing a transition metal-carbon based catalyst according to claim 4, wherein the reducing atmosphere comprises methane and hydrogen, the volume ratio of methane to hydrogen is 1 (2-5), and the heat treatment comprises: heating to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours; or alternatively, the process may be performed,
The reducing atmosphere comprises nitrogen and hydrogen, the volume ratio of the nitrogen to the hydrogen is (0.5-3) 1, and the heat treatment comprises: heating to 700-1000 ℃ at a speed of 2-10 ℃/min and performing heat treatment at 700-1000 ℃ for 1-4 hours.
7. The method for preparing a transition metal-carbon-based catalyst according to any one of claims 4 to 6, wherein the step of preparing the doped carbon-based carrier comprises: mixing a biomass carbon source, a doping raw material and an alkali metal activator, pyrolyzing for 1-4 hours at 600-900 ℃ in an inert atmosphere, then carrying out acid washing, water washing and drying to prepare the doped carbon-based carrier, wherein the mass ratio of the biomass carbon source to the doping raw material to the alkali metal activator is (0.5-1): (2-5): (1-3), and the doping raw material comprises any one or more of a nitrogen source, a phosphorus source and a boron source.
8. The method for preparing a transition metal-carbon based catalyst according to claim 7, wherein the step of preparing the doped carbon-based carrier satisfies at least one of the following conditions:
(1) The biomass carbon source comprises any one or more of lignin and cellulose;
(2) The doping raw materials comprise any one or more of urea, dicyandiamide, melamine and ammonia gas;
(3) The alkali metal activator comprises NaHCO 3 Any one or more of KOH and NaOH.
9. The use of a transition metal-carbon based catalyst according to any one of claims 1 to 3 in a reverse water vapor shift reaction.
10. The use according to claim 9, wherein the reverse water vapor shift reaction satisfies at least one of the following conditions:
(1) In the reverse water-gas shift reaction, the volume ratio of carbon dioxide to hydrogen is 1 (2-8);
(2) The temperature of the reverse water-gas shift reaction is 300-500 ℃;
(3) In the reverse water-gas shift reaction, the mass airspeed is 16000mL/g/h to 800000mL/g/h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310552142.8A CN116273134B (en) | 2023-05-17 | 2023-05-17 | Transition metal-carbon-based catalyst and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310552142.8A CN116273134B (en) | 2023-05-17 | 2023-05-17 | Transition metal-carbon-based catalyst and preparation method and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116273134A true CN116273134A (en) | 2023-06-23 |
| CN116273134B CN116273134B (en) | 2023-08-15 |
Family
ID=86796299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310552142.8A Active CN116273134B (en) | 2023-05-17 | 2023-05-17 | Transition metal-carbon-based catalyst and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116273134B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109433242A (en) * | 2018-11-15 | 2019-03-08 | 厦门大学 | A kind of N doping porous charcoal load molybdenum carbide catalyst and the preparation method and application thereof |
| CN113877613A (en) * | 2021-07-22 | 2022-01-04 | 中国林业科学研究院林产化学工业研究所 | CO (carbon monoxide)2Hydrogenated biomass charcoal-based transition metal catalyst and preparation method thereof |
| CN113908833A (en) * | 2020-10-23 | 2022-01-11 | 源创核新(北京)新材料科技有限公司 | Reverse water gas shift catalyst and preparation method and application thereof |
| CN114086208A (en) * | 2021-12-17 | 2022-02-25 | 澳门大学 | Composite electrode material for producing hydrogen by electrolyzing water and preparation method thereof |
| CN115786945A (en) * | 2022-11-18 | 2023-03-14 | 天津大学 | Nitrogen-doped carbon nanotube-loaded molybdenum carbide catalyst and preparation method and application thereof |
-
2023
- 2023-05-17 CN CN202310552142.8A patent/CN116273134B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109433242A (en) * | 2018-11-15 | 2019-03-08 | 厦门大学 | A kind of N doping porous charcoal load molybdenum carbide catalyst and the preparation method and application thereof |
| CN113908833A (en) * | 2020-10-23 | 2022-01-11 | 源创核新(北京)新材料科技有限公司 | Reverse water gas shift catalyst and preparation method and application thereof |
| CN113877613A (en) * | 2021-07-22 | 2022-01-04 | 中国林业科学研究院林产化学工业研究所 | CO (carbon monoxide)2Hydrogenated biomass charcoal-based transition metal catalyst and preparation method thereof |
| CN114086208A (en) * | 2021-12-17 | 2022-02-25 | 澳门大学 | Composite electrode material for producing hydrogen by electrolyzing water and preparation method thereof |
| CN115786945A (en) * | 2022-11-18 | 2023-03-14 | 天津大学 | Nitrogen-doped carbon nanotube-loaded molybdenum carbide catalyst and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| YING MA ET AL.: "Molybdenum carbide clusters for thermal conversion of CO 2 to CO via reverse water-gas shift reaction", 《JOURNAL OF ENERGY CHEMISTRY》, vol. 50, pages 38 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116273134B (en) | 2023-08-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yan et al. | Catalytic graphitization of kraft lignin to graphene-based structures with four different transitional metals | |
| Pudukudy et al. | Catalytic decomposition of methane over rare earth metal (Ce and La) oxides supported iron catalysts | |
| Zhang et al. | Commercial Fe-or Co-containing carbon nanotubes as catalysts for NH 3 decomposition | |
| Junke et al. | Characterization and analysis of carbon deposited during the dry reforming of methane over Ni/La2O3/Al2O3 catalysts | |
| Awadallah et al. | Impact of group VI metals addition to Co/MgO catalyst for non-oxidative decomposition of methane into COx-free hydrogen and carbon nanotubes | |
| Pang et al. | Activated carbon supported molybdenum carbides as cheap and highly efficient catalyst in the selective hydrogenation of naphthalene to tetralin | |
| Surisetty et al. | Effect of Rh promoter on MWCNT-supported alkali-modified MoS2 catalysts for higher alcohols synthesis from CO hydrogenation | |
| CN110947388B (en) | Graphene aerogel supported nickel catalyst and preparation method and application thereof | |
| CN111372681A (en) | Catalyst and process for tunable substrate growth of multi-walled carbon nanotubes | |
| EP1782884A1 (en) | Catalyst based on MgO or alumina nanoporous support and preparation of the same | |
| Aramouni et al. | Molybdenum and nickel-molybdenum nitride catalysts supported on MgO-Al2O3 for the dry reforming of methane | |
| Xu et al. | Facile synthesis of stable Mo2N nanobelts with high catalytic activity for ammonia decomposition | |
| Shi et al. | Impact of nickel phosphides over Ni/SiO2 catalysts in dry methane reforming | |
| US20170283259A1 (en) | Nano-Structured Catalysts | |
| Malhi et al. | The promotional effects of carbon nanotube on Fe5C2-ZnO catalysts for CO2 hydrogenation to heavy olefins | |
| Park et al. | Effect of reduction conditions of Mo-Fe/MgO on the formation of carbon nanotube in catalytic methane decomposition | |
| Alharthi | Nickel-iron catalyst for decomposition of methane to hydrogen and filamentous carbon: Effect of calcination and reaction temperatures | |
| Meng et al. | Synthesis and characterization of molybdenum carbide catalysts on different carbon supports | |
| Han et al. | High selective synthesis of methanol from CO2 over Mo2C@ NSC | |
| Cao et al. | High-density MoCx nanoclusters anchored on nanodiamond-derived nanocarbon as a robust CO2 reduction catalyst for syngas production | |
| Ashok et al. | Catalytic decomposition of CH4 over Ni-Al2O3-SiO2 catalysts: Influence of pretreatment conditions for the production of H2 | |
| Ko et al. | Effects of support porosity of Co-Mo/MgO catalyst on methane catalytic decomposition for carbon and hydrogen production | |
| Shukrullah et al. | Synthesis of MWCNT Forests with Alumina-Supported Fe 2 O 3 Catalyst by Using a Floating Catalyst Chemical Vapor Deposition Technique | |
| CN116273134B (en) | Transition metal-carbon-based catalyst and preparation method and application thereof | |
| Kim et al. | Fabrication of carbon nanotube with high purity and crystallinity by methane decomposition over ceria-supported catalysts |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |