CN109382117A - A kind of tripod shape platinum palladium-copper alloy catalyst and preparation method thereof of catalytic oxidation-reduction reaction - Google Patents
A kind of tripod shape platinum palladium-copper alloy catalyst and preparation method thereof of catalytic oxidation-reduction reaction Download PDFInfo
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- CN109382117A CN109382117A CN201811226822.6A CN201811226822A CN109382117A CN 109382117 A CN109382117 A CN 109382117A CN 201811226822 A CN201811226822 A CN 201811226822A CN 109382117 A CN109382117 A CN 109382117A
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 title claims abstract description 164
- 229910052697 platinum Inorganic materials 0.000 title claims abstract description 82
- 239000003054 catalyst Substances 0.000 title claims abstract description 44
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- 230000003197 catalytic effect Effects 0.000 title claims description 21
- 238000006479 redox reaction Methods 0.000 title claims description 20
- 229910000881 Cu alloy Inorganic materials 0.000 title claims description 17
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 142
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 71
- 239000002253 acid Substances 0.000 claims abstract description 51
- 239000010949 copper Substances 0.000 claims abstract description 49
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910052802 copper Inorganic materials 0.000 claims abstract description 47
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 claims abstract description 46
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 40
- IOLCXVTUBQKXJR-UHFFFAOYSA-M potassium bromide Chemical compound [K+].[Br-] IOLCXVTUBQKXJR-UHFFFAOYSA-M 0.000 claims abstract description 26
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 25
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims abstract description 25
- 239000000460 chlorine Substances 0.000 claims abstract description 25
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 25
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 25
- 239000011734 sodium Substances 0.000 claims abstract description 25
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims abstract description 24
- 229960005070 ascorbic acid Drugs 0.000 claims abstract description 23
- 235000010323 ascorbic acid Nutrition 0.000 claims abstract description 23
- 239000011668 ascorbic acid Substances 0.000 claims abstract description 23
- 238000002156 mixing Methods 0.000 claims abstract description 22
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000001301 oxygen Substances 0.000 claims abstract description 14
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 14
- 238000000034 method Methods 0.000 claims description 23
- 238000006722 reduction reaction Methods 0.000 claims description 18
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 238000001035 drying Methods 0.000 abstract description 9
- 238000005119 centrifugation Methods 0.000 abstract description 8
- 238000005406 washing Methods 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 4
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 abstract 1
- 230000035484 reaction time Effects 0.000 abstract 1
- 238000004502 linear sweep voltammetry Methods 0.000 description 18
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 11
- 229910052739 hydrogen Inorganic materials 0.000 description 11
- 239000001257 hydrogen Substances 0.000 description 11
- 239000002245 particle Substances 0.000 description 10
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- 229910021607 Silver chloride Inorganic materials 0.000 description 8
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 8
- 238000006555 catalytic reaction Methods 0.000 description 7
- 239000002105 nanoparticle Substances 0.000 description 7
- 238000012546 transfer Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000002159 nanocrystal Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000002604 ultrasonography Methods 0.000 description 3
- 206010013786 Dry skin Diseases 0.000 description 2
- 229920000557 Nafion® Polymers 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 210000004027 cell Anatomy 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 238000002484 cyclic voltammetry Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 229910021397 glassy carbon Inorganic materials 0.000 description 2
- 238000002173 high-resolution transmission electron microscopy Methods 0.000 description 2
- 239000013067 intermediate product Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000001507 sample dispersion Methods 0.000 description 2
- 238000010189 synthetic method Methods 0.000 description 2
- 229910021642 ultra pure water Inorganic materials 0.000 description 2
- 239000012498 ultrapure water Substances 0.000 description 2
- QGLWBTPVKHMVHM-KTKRTIGZSA-N (z)-octadec-9-en-1-amine Chemical compound CCCCCCCC\C=C/CCCCCCCCN QGLWBTPVKHMVHM-KTKRTIGZSA-N 0.000 description 1
- OTEKOJQFKOIXMU-UHFFFAOYSA-N 1,4-bis(trichloromethyl)benzene Chemical compound ClC(Cl)(Cl)C1=CC=C(C(Cl)(Cl)Cl)C=C1 OTEKOJQFKOIXMU-UHFFFAOYSA-N 0.000 description 1
- 238000001016 Ostwald ripening Methods 0.000 description 1
- 229910002845 Pt–Ni Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000011549 displacement method Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 239000004210 ether based solvent Substances 0.000 description 1
- 230000002209 hydrophobic effect Effects 0.000 description 1
- 230000001404 mediated effect Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 238000003541 multi-stage reaction Methods 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 230000033116 oxidation-reduction process Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 238000009790 rate-determining step (RDS) Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 230000008117 seed development Effects 0.000 description 1
- 238000001338 self-assembly Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 229920000428 triblock copolymer Polymers 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
- B01J23/8926—Copper and noble metals
-
- B01J35/33—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B1/00—Electrolytic production of inorganic compounds or non-metals
- C25B1/01—Products
- C25B1/28—Per-compounds
- C25B1/30—Peroxides
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
- C25B11/097—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds comprising two or more noble metals or noble metal alloys
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/90—Selection of catalytic material
- H01M4/92—Metals of platinum group
- H01M4/921—Alloys or mixtures with metallic elements
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Abstract
A kind of tripod shape platinum palladium copper oxygen reduction catalyst and preparation method thereof matches chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution of the concentration between 5~50mM, hydrochloric acid solution and concentration ascorbic acid solution 0.05~0.2M between of the concentration between 1~10M respectively；Chlorine palladium acid sodium, chloroplatinic acid and the copper chloride solution mixing that total volume is 4.5mL are taken respectively, and the hydrochloric acid solution that 0.1~1mL has been prepared then is added, adds the F127 between potassium bromide and 0.01~0.1g between 0.1~1g, is uniformly mixed；Finally add the ascorbic acid solution of 1~5mL；It after solution is sufficiently mixed, is placed in oil bath pan and is heated between 50~150 DEG C, after reacting 1~10h, washing, centrifugation, drying obtain platinum palladium copper tripod shape oxygen reduction catalyst.Preparation process of the present invention is simple, and the reaction time is short, and material obtained has excellent electrochemical redox performance at normal temperatures and pressures.
Description
(1) technical field
The present invention relates to a kind of tripod shape platinum palladium-copper alloy catalyst and preparation method thereof of catalytic oxidation-reduction reaction, should
Catalyst can be used for the research of electrochemical catalytic oxidation reduction reaction.
(2) background technique
The chemical energy being stored in organic matter and hydrogen can be converted to electric energy by proton membrane fuel battery, this is to replacementization
Stone fuel has very important significance.Convert field in energy, platinum-base material catalyst is widely used, however, high carrying capacity and
Height spends the further development for seriously hindering platinum-base material and heavy industrialization.And pure platinum catalyst is easy to roll into a ball
It is poly-, poisoned by intermediate product, active site is occupied, and this seriously inhibits the absorption of new reactant, affects catalytic efficiency
And activity.Noble metal nano crystal has attracted extensive concern, wherein since dendritic crystal can effectively improve catalytic activity and steady
It is qualitative, attract the extensive concern of researcher in various electro-catalysis application.Reasonably adjusting size, pattern and composition
It is a kind of effective ways for obtaining and there are more dendritic crystals of electrocatalysis characteristic.For example, preparation has the platinum of hyperbranched structure
Nickel nanocrystal, be applied to electro-catalysis methanol oxidation (Z.Q.Niu, D.S.Wang, R.Yu, Q.Peng, Y.D.Li,
Highly Branched Pt–Ni Nanocrystals Enclosed by Stepped Surface for Methanol
Oxidation.Chem.Sci.2012,3,1925-1929).It prepares nanometer thorn-like palladium copper Au catalyst and is used for electrocatalytic oxidation also
Original reaction (H.Wang, S.Yin, Y.Li, H.Yu, C.Li, K.Deng, Y.Xu, X.Li, H.Xue and L.Wang, One-Step
Fabrication of Tri-Metallic PdCuAu Nanothorn Assemblies as an Efficient
Catalyst for Oxygen Reduction Reaction.J.Mater.Chem.A,2018,6,3642-3648).Especially
It is to control size and pattern to increase specific surface area effectively to improve the utilization rate of noble metal, control composition can provide more
Good electronic structure effect and contract effect.
In various dendritic noble metal base nanometer crystal bodies, it is excellent that tripod presents apparent structure in electro-catalysis
Gesture.Ostwald ripening be easy to cause the loss of active site, and the tripod of self-supporting is not readily susceptible to influence.Separately
Outside, the dendritic of opening provides accessible surface area and high permeability.Likewise, researchers are dedicated to synthesizing more metals
Tripod catalyst, wherein platinum base tripod shape catalyst is paid high attention to.
Only have a small amount of method to synthesize platinum tripod at present, mainly there is displacement method, seed mediated growth method and chemical etching method.These
Synthetic method depends on multistep reaction, organic solution and high temperature.For example, the platinum tripod of plane is logical at 130 DEG C and 160 DEG C
It crosses two-step method and prepares (S.Maksimuk, X.Teng and H.Yang, Planar Tripods of in hexichol ether solvents
Platinum:Formation and Self-Assembly.Phys.Chem.Chem.Phys.,2006,8,4660–4663.)。
(Camargo, B.C. is prepared in the 150 DEG C of reactions in oleyl amine solvent of the platinum nanometer star of class tripod shape；Lassagne,B.；
Arenal,R.；Gatel,C.；Blon,T.；Viau,G.；Lacroix,L.-M.Escoffier,W.Platinum Tripods
as Nanometric Frequency Multiplexing Devices.Nanoscale.2017,9,14635–14640).By
It is lower in platinum tripod yield, it is difficult expanding production.So designing the flexible and mild synthetic method of one kind has height to synthesize
The platinum tripod of yield is expected to.Reducing the size of platinum tripod, the length for increasing branch can be further improved catalytic activity,
Increase platinum utilization.Moreover, it is noted that the surface for the platinum tripod reported in the past is smooth, so, dexterously
The surface of design tripod is very important to active site is further increased.
At present there is the platinum base tripod controllably formed to be seldom reported.Platinum and other metals form alloy and are capable of providing one
A advantageous electronic effect, to be conducive to inhibit the oxidation of platinum.The surface texture and composition of platinum tripod and ingehious design
In conjunction with the platinum based catalyst with high activity can be help to obtain.
Therefore, a kind of simple one-step method is designed, a kind of high yield is directly synthesized in water phase, it is living to redox reaction
Property high, stability is good and the tripod shape multimetal reforming catalyst of methanol tolerant performance in elctro-catalyst preparation with very important
Research significance.
(3) summary of the invention
It is an object of the present invention to provide a kind of tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction and its preparations
Method, and catalytic electrochemical redox reaction is studied.
The technical solution adopted by the present invention is that:
A kind of tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, prepares by the following method:
(1) match chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution of the concentration between 5~50mM respectively, concentration is in 1~10M
Between ascorbic acid solution between 0.05~0.2M of hydrochloric acid solution and concentration；
(2) taking total volume respectively is the chlorine palladium acid sodium of 4.5mL, chloroplatinic acid and copper chloride solution mixing, then it is added 0.1~
The hydrochloric acid solution that 1mL has been prepared adds the F127 between potassium bromide and 0.01~0.1g between 0.1~1g, is uniformly mixed；
Finally add the ascorbic acid solution of 1~5mL；
(3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 50~150 DEG C, after reacting 1~10h, washing,
Centrifugation, drying, obtain platinum palladium copper tripod shape oxygen reduction catalyst.
The selection of reaction condition has great influence to the structure for preparing platinum palladium copper, and the present invention selects triblock copolymer
F127 is can to become good end-capping reagent and structure directing agent because of the hydrophobic design feature in the hydrophilic centre in its both ends, can
To efficiently control the growth of nucleus and prevent from reuniting.In addition, Cu has low stacking fault energy, Cu is introduced2+It can be in nucleation rank
The Seed Development of Duan Jifa sheet may eventually lead to the formation of dendritic nanocrystal.And Br-Face-centred Cubic Metals can be adsorbed on
(100) on crystal face, the growth of metal on (100) crystal face can be selectively prevented, the growth of dendrite is ultimately facilitated.It is preparing
In the process, the ratio that object is added before changing can control the pattern and structure of platinum palladium copper.
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
(1) match chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution of the concentration between 5~50mM respectively, concentration is in 1~10M
Between hydrochloric acid solution, ascorbic acid solution of the concentration between 0.05~0.2M；
(2) taking total volume respectively is the chlorine palladium acid sodium of 4.5mL, chloroplatinic acid and copper chloride solution mixing, then it is added 0.1~
Hydrochloric acid solution between 1mL adds the F127 between potassium bromide and 0.01~0.1g between 0.1~1g, is uniformly mixed；Most
Add the ascorbic acid solution of 1~5mL afterwards, ultrasonic mixing 20 minutes；
(3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 50~150 DEG C, after reacting 1~10h, washing,
Centrifugation, drying, obtain platinum palladium copper tripod shape oxygen reduction catalyst.
Further, control chlorine palladium acid sodium, chloroplatinic acid, copper chloride, the concentration and volume of ascorbic acid, potassium bromide and F127's
Amount, and the temperature and time of reaction control the pattern and structure of platinum palladium copper.
Electrochemical catalytic oxidation reduction reaction, specific performance test operating procedure are carried out at normal temperatures and pressures are as follows:
(1) sample dispersion of 1~5mg is weighed in ultrapure water, and ultrasound obtains uniform dispersion liquid in 30 minutes, takes 1~10 μ
L drop drips 1~10 μ L Nafion solution (0.5wt%) after glassy carbon electrode surface, 50 DEG C of dryings and is covered on catalyst surface, system
At working electrode.Platinum electrode is used as to electrode simultaneously, and Ag/AgCl electrode carries out oxygen as reference electrode composition three-electrode system
Change reduction test；
(2) before testing, the perchloric acid solution of 0.1M is added in electrolytic cell, logical 30 minutes oxygen keeps its solution oxygen full
With the test program of selection cyclic voltammetry and linear sweep voltammetry, with computer monitor working electrode in the case where difference sweeps speed
Current conditions.It is last to calculate Tafel slope according to the data measured and corresponding formula, shift electron number and peroxidating
Hydrogen yield evaluates the hydrogen reduction performance of catalyst.
The tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction provided by the present invention and preparation method thereof
Beneficial effect is mainly reflected in:
(1) preparation method is simple, directly obtains product by one-step method, and reaction condition is mild, tripod shape products collection efficiency
It is high.
(2) pattern and structure of platinum palladium copper be can control by the concentration and volume that change presoma.
(3) the platinum palladium copper tripod shape nanostructured materials catalyst synthesized presents activity outstanding in redox reaction
And stability, platinum-base material have very high application prospect as elctro-catalyst.
(4) Detailed description of the invention
Fig. 1 is that the SEM of 1 platinum palladium copper tripod of specific embodiments of the present invention schemes.
Fig. 2 is that the TEM and HRTEM of 1 platinum palladium copper tripod of specific embodiments of the present invention scheme.
Fig. 3 is the XRD diagram of 1 platinum palladium copper tripod of specific embodiments of the present invention.
Fig. 4 is that the XPS of 1 platinum palladium copper tripod of specific embodiments of the present invention schemes.
Fig. 5 is linear sweep voltammetry of the 1 platinum palladium copper tripod of specific embodiments of the present invention under 1600 turns, and Ta Feier is oblique
Rate, linear sweep voltammetry curve and transfer electron number under every speed.
Fig. 6 is the rotation counter offer electric current of 1 platinum palladium copper tripod of specific embodiments of the present invention, shifts electron number and peroxidating
Hydrogen yield, the linear sweep voltammetry curve and polarogram current-time curvel of 5000 circle front and backs.
Fig. 7 is that the SEM of 2 platinum palladium copper racemosus nano particle of specific embodiments of the present invention schemes.
Fig. 8 is linear sweep voltammetry of the 2 platinum palladium copper racemosus nano particle of specific embodiments of the present invention under 1600 turns, tower
Fei Er slope.
Fig. 9 is that the SEM of 3 platinum palladium copper acicular nanometer particle of specific embodiments of the present invention schemes.
Figure 10 is linear sweep voltammetry of the 2 platinum palladium copper acicular nanometer particle of specific embodiments of the present invention under 1600 turns,
Tafel slope.
(5) specific embodiment
The present invention is described further combined with specific embodiments below, but protection scope of the present invention is not limited in
This:
Referring to Fig.1~Figure 10, in the present embodiment, the redox performance test to the platinum palladium copper product is in CHI
It is carried out on 760D electrochemical workstation, operating process are as follows:
The first step weighs the sample dispersion of 2mg in ultrapure water, and ultrasound obtains uniform dispersion liquid in 30 minutes, takes 5 μ L drops
5 μ L Nafion solutions (0.5wt%) are dripped after glassy carbon electrode surface, 50 DEG C of dryings and are covered on catalyst surface, and work electricity is made
Pole.Platinum electrode is used as to electrode simultaneously, and Ag/AgCl electrode carries out redox survey as reference electrode composition three-electrode system
Examination；
The perchloric acid solution of 0.1M is added before testing in second step in electrolytic cell, logical 30 minutes oxygen makes its solution oxygen
Saturation selects the test program of cyclic voltammetry and linear sweep voltammetry, sweeps speed in difference with computer monitor working electrode
Under current conditions.It is last to calculate Tafel slope according to the data measured and corresponding formula, shift electron number and peroxide
Change hydrogen yield to evaluate the hydrogen reduction performance of catalyst.
Embodiment 1:
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
1) respectively with concentration be 20mM chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution, concentration be 6M hydrochloric acid solution and
Concentration is the ascorbic acid solution of 0.1M；
2) 2.5mL chlorine palladium acid sodium, 1mL chloroplatinic acid and the mixing of 1mL copper chloride solution are taken respectively, and 0.2mL hydrochloric acid is then added
Solution, adds 200mg potassium bromide and 50mg F127, and ultrasonic mixing is uniform；2mL ascorbic acid solution is finally added, ultrasound
Mixing 20 minutes；
3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 95 DEG C, after reacting 3h, washing, centrifugation, drying,
Obtain platinum palladium copper tripod shape oxygen reduction catalyst.
The SEM figure of the platinum palladium copper tripod of acquisition is referring to Fig. 1.The TEM figure of the platinum palladium copper tripod of acquisition is referring to fig. 2.It obtains
The XRD diagram of the platinum palladium copper tripod obtained is referring to Fig. 3.The XPS figure of the platinum palladium copper tripod of acquisition is referring to fig. 4.The platinum palladium copper of acquisition
Linear sweep voltammetry of the tripod under 1600 turns, Tafel slope, linear sweep voltammetry and transfer electronics under every speed
Number is referring to Fig. 5.The rotation counter offer electric current of the platinum palladium copper tripod of acquisition shifts electron number and hydrogen peroxide yield, before 5000 enclose
Linear sweep voltammetry curve and polarogram current-time curvel afterwards is referring to Fig. 6.
Schemed by SEM as it can be seen that the yield of tripod shape platinum palladium copper is close to 100%, each particle is mutually independent by three
Branch forms, and the angle between every two branch is 120 °, this is typical tripod structure.Find out from TEM figure, each branch is not
Be it is smooth, above be made of again many small branches, it is living to increase electrochemistry that this structure can effectively increase specific surface area
Property site.Found out by HRTEM figure, the edge of branch have clearly atom ladder this to redox reaction have very high work
Property.By XRD and XPS analysis, platinum palladium-copper alloy is formed.It can be seen that platinum palladium copper tripod by linear sweep voltammetry curve
Take-off potential (0.71V vs.Ag/AgCl) and half wave potential (0.65V vs.Ag/AgCl) with very positive catalytic oxidation-reduction.
According to linear sweep voltammetry curve calculate Tafel slope be 60mV dec-1, it was demonstrated that the first electronics during hydrogen reduction
Transfer is rate determining step.By the linear sweep voltammetry curve and transfer electron number under different rotating speeds, counter offer electric current is rotated,
Transfer electron number and hydrogen peroxide yield can be seen that and four electron reactions have occurred, and intermediate product is few.From 5000 circle front and backs
Linear sweep voltammetry curve and polarogram current-time curvel can be seen that platinum palladium copper tripod with good stability.
Embodiment 2:
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
1) respectively with concentration be 20mM chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution, concentration be 6M hydrochloric acid solution and
Concentration is the ascorbic acid solution of 0.1M；
2) 3mL chlorine palladium acid sodium, 0.75mL chloroplatinic acid and the mixing of 0.75mL copper chloride solution are taken respectively, and 0.2mL is then added
Hydrochloric acid solution, adds 200mg potassium bromide and 50mg F127, and ultrasonic mixing is uniform.2mL ascorbic acid solution is finally added,
Ultrasonic mixing 20 minutes；
3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 95 DEG C, after reacting 3h, washing, centrifugation, drying,
Obtain the platinum palladium copper racemosus nano particle oxygen reduction catalyst.
The SEM figure of platinum palladium copper racemosus nano particle is obtained referring to Fig. 7, obtains platinum palladium copper racemosus nano particle under 1600 turns
Linear sweep voltammetry and Tafel slope referring to Fig. 8.
Schemed by SEM as it can be seen that platinum palladium copper racemosus nano particle is formed.This is mainly due to the ratios for changing presoma to cause
Platinum palladium copper pattern changes.It can be seen that the catalysis that platinum palladium copper racemosus nano particle has calibration by linear sweep voltammetry curve
The take-off potential (0.69V vs.Ag/AgCl) and half wave potential (0.63V vs.Ag/AgCl) of hydrogen reduction.It is lied prostrate according to linear scan
Peace curve calculate Tafel slope be 77mV dec-1, it was demonstrated that the transfer of the first electronics is rate control during hydrogen reduction
Step.
Embodiment 3:
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
1) respectively with concentration be 20mM chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution, concentration be 6M hydrochloric acid solution and
Concentration is the ascorbic acid solution of 0.1M；
2) 1.5mL chlorine palladium acid sodium, 1.5mL chloroplatinic acid and the mixing of 1.5mL copper chloride solution are taken respectively, and 0.2mL is then added
Hydrochloric acid solution, adds 200mg potassium bromide and 50mg F127, and ultrasonic mixing is uniform.2mL ascorbic acid solution is finally added,
Ultrasonic mixing 20 minutes；
3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 95 DEG C, after reacting 3h, washing, centrifugation, drying,
Obtain the platinum palladium copper acicular nanometer particle oxygen reduction catalyst.
The SEM figure of platinum palladium copper acicular nanometer particle is obtained referring to Fig. 9, obtains platinum palladium copper acicular nanometer particle under 1600 turns
Linear sweep voltammetry and Tafel slope referring to Figure 10.
Schemed by SEM as it can be seen that platinum palladium copper acicular nanometer particle is formed.This is mainly due to the ratios for changing presoma to cause
Platinum palladium copper pattern changes.It can be seen that the catalysis that platinum palladium copper acicular nanometer particle has calibration by linear sweep voltammetry curve
The take-off potential (0.69V vs.Ag/AgCl) and half wave potential (0.64V vs.Ag/AgCl) of hydrogen reduction.It is lied prostrate according to linear scan
Peace curve calculate Tafel slope be 88mV dec-1, it was demonstrated that the transfer of the first electronics is rate control during hydrogen reduction
Step.
Embodiment 4:
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
1) chlorine palladium acid sodium, chloroplatinic acid and the copper chloride solution for being respectively 5mM with concentration, concentration are the hydrochloric acid solution of 1M and dense
Degree is the ascorbic acid solution of 0.05M；
2) 3mL chlorine palladium acid sodium, 1mL chloroplatinic acid and the mixing of 0.5mL copper chloride solution are taken respectively, and 0.1mL hydrochloric acid is then added
Solution, adds the potassium bromide of 0.1g and the F127 of 0.01g, and ultrasonic mixing is uniform；The ascorbic acid for finally adding 1mL is molten
Liquid, ultrasonic mixing 20 minutes；
3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated to 50 DEG C, after reacting 1h, washing, centrifugation, drying are obtained
Catalyst.
Due in this process, the concentration catalysis that is very low, therefore being synthesized of chlorine palladium acid sodium, chloroplatinic acid and copper chloride
Agent particle very little is difficult to be centrifuged out from solution, and potassium bromide and the amount of F127 are also fewer, is difficult to regulate and control catalyst
Pattern, moreover, reaction temperature is relatively low, it cannot be by chlorination copper reduction, therefore, it is difficult to synthesize the platinum palladium-copper alloy of tripod shape
Catalyst.
Embodiment 5:
A kind of preparation method of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, the method includes such as
Lower step:
1) respectively with concentration be 50mM chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution, concentration be 10M hydrochloric acid solution and
Concentration is the ascorbic acid solution of 0.5M；
2) 1.5mL chlorine palladium acid sodium, 1.5mL chloroplatinic acid and the mixing of 1.5mL copper chloride solution are taken respectively, and 1mL salt is then added
Acid solution, adds the potassium bromide of 1g and the F127 of 0.1g, and ultrasonic mixing is uniform；The ascorbic acid solution of 5mL is finally added,
Ultrasonic mixing 20 minutes；
3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated to 150 DEG C, it is washing, centrifugation, dry after back flow reaction 10h
It is dry, obtain catalyst.
Due in this process, the concentration catalysis that is very big, therefore being synthesized of chlorine palladium acid sodium, chloroplatinic acid and copper chloride
Agent particle is also bigger；In addition increase hydrochloric acid amount after, the reducing power of ascorbic acid can be greatly reduced, make it difficult to by
Chlorine palladium acid sodium, chloroplatinic acid and chlorination copper reduction, therefore the catalyst synthesized is difficult to obtain the platinum palladium-copper alloy of tripod shape and urges
Agent.
Claims (3)
1. a kind of tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction, prepares by the following method:
(1) match chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution of the concentration between 5~50mM respectively, concentration is between 1~10M
Ascorbic acid solution between 0.05~0.2M of hydrochloric acid solution and concentration；
(2) chlorine palladium acid sodium, chloroplatinic acid and the copper chloride solution mixing that total volume is 4.5mL are taken respectively, and 0.1~1mL is then added
The hydrochloric acid solution prepared adds the F127 between potassium bromide and 0.01~0.1g between 0.1~1g, is uniformly mixed；Most
The ascorbic acid solution of 1~5mL is added afterwards；
(3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 50~150 DEG C, after reacting 1~10h, wash, be centrifuged,
It is dry, obtain platinum palladium copper tripod shape oxygen reduction catalyst.
2. a kind of preparation side of the tripod shape platinum palladium-copper alloy catalyst of catalytic oxidation-reduction reaction as described in claim 1
Method, which is characterized in that described method includes following steps:
(1) match chlorine palladium acid sodium, chloroplatinic acid and copper chloride solution of the concentration between 5~50mM respectively, concentration is between 1~10M
Hydrochloric acid solution, ascorbic acid solution of the concentration between 0.05~0.2M；
(2) chlorine palladium acid sodium, chloroplatinic acid and the copper chloride solution mixing that total volume is 4.5mL are taken respectively, and 0.1~1mL is then added
Between hydrochloric acid solution, add the F127 between potassium bromide and 0.01~0.1g between 0.1~1g, be uniformly mixed；Finally
Add the ascorbic acid solution of 1~5mL, ultrasonic mixing 20 minutes；
(3) it after solution is sufficiently mixed, is placed in oil bath pan and is heated between 50~150 DEG C, after reacting 1~10h, wash, be centrifuged,
It is dry, obtain platinum palladium copper tripod shape oxygen reduction catalyst.
3. method according to claim 2, which is characterized in that control chlorine palladium acid sodium, chloroplatinic acid, copper chloride, ascorbic acid
The amount of concentration and volume, potassium bromide and F127, and the temperature and time of reaction control the pattern and structure of platinum palladium copper.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110586128A (en) * | 2019-08-29 | 2019-12-20 | 浙江工业大学 | Platinum-palladium-nickel truncated octahedral porous nanocage electrocatalyst and preparation method thereof |
| CN111180750A (en) * | 2020-01-03 | 2020-05-19 | 西北工业大学 | AgPdIr nano alloy and preparation and use method thereof |
| CN112935273A (en) * | 2021-01-26 | 2021-06-11 | 哈尔滨理工大学 | Method for preparing CuPt alloy nanoparticles at room temperature |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105396600A (en) * | 2015-11-10 | 2016-03-16 | 中国科学院福建物质结构研究所 | Pd5.12Cu dendritic nanocrystalline catalyst as well as preparation and application thereof |
| CN105478794A (en) * | 2015-12-11 | 2016-04-13 | 中国科学院深圳先进技术研究院 | Platinum-copper alloy nano particle and preparation method thereof |
| CN106732556A (en) * | 2016-11-25 | 2017-05-31 | 安徽师范大学 | A kind of porous platinum/palldium alloy nanoparticle catalyst, preparation method and applications |
-
2018
- 2018-10-22 CN CN201811226822.6A patent/CN109382117A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105396600A (en) * | 2015-11-10 | 2016-03-16 | 中国科学院福建物质结构研究所 | Pd5.12Cu dendritic nanocrystalline catalyst as well as preparation and application thereof |
| CN105478794A (en) * | 2015-12-11 | 2016-04-13 | 中国科学院深圳先进技术研究院 | Platinum-copper alloy nano particle and preparation method thereof |
| CN106732556A (en) * | 2016-11-25 | 2017-05-31 | 安徽师范大学 | A kind of porous platinum/palldium alloy nanoparticle catalyst, preparation method and applications |
Non-Patent Citations (1)
| Title |
|---|
| HONGJING WANG ET AL.: "Direct fabrication of tri-metallic PtPdCu tripods with branched exteriors for the oxygen reduction reaction", 《J. MATER. CHEM. A》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110586128A (en) * | 2019-08-29 | 2019-12-20 | 浙江工业大学 | Platinum-palladium-nickel truncated octahedral porous nanocage electrocatalyst and preparation method thereof |
| CN111180750A (en) * | 2020-01-03 | 2020-05-19 | 西北工业大学 | AgPdIr nano alloy and preparation and use method thereof |
| CN112935273A (en) * | 2021-01-26 | 2021-06-11 | 哈尔滨理工大学 | Method for preparing CuPt alloy nanoparticles at room temperature |
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