CN109576730B - Preparation method and application of iron-modified cobaltosic oxide nanosheet array electrode - Google Patents
Preparation method and application of iron-modified cobaltosic oxide nanosheet array electrode Download PDFInfo
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- CN109576730B CN109576730B CN201811386271.XA CN201811386271A CN109576730B CN 109576730 B CN109576730 B CN 109576730B CN 201811386271 A CN201811386271 A CN 201811386271A CN 109576730 B CN109576730 B CN 109576730B
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- 239000002135 nanosheet Substances 0.000 title claims abstract description 131
- UBEWDCMIDFGDOO-UHFFFAOYSA-N cobalt(2+);cobalt(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[O-2].[Co+2].[Co+3].[Co+3] UBEWDCMIDFGDOO-UHFFFAOYSA-N 0.000 title claims abstract description 86
- 238000002360 preparation method Methods 0.000 title claims abstract description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 181
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 173
- 239000004744 fabric Substances 0.000 claims abstract description 172
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 53
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 27
- 239000001301 oxygen Substances 0.000 claims abstract description 27
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 27
- 238000000137 annealing Methods 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 18
- 238000005530 etching Methods 0.000 claims abstract description 8
- 150000001450 anions Chemical class 0.000 claims abstract description 7
- 238000012545 processing Methods 0.000 claims abstract description 7
- 238000002791 soaking Methods 0.000 claims abstract description 7
- 239000012921 cobalt-based metal-organic framework Substances 0.000 claims description 46
- -1 potassium ferricyanide Chemical compound 0.000 claims description 44
- GIWQSPITLQVMSG-UHFFFAOYSA-N 1,2-dimethylimidazole Chemical compound CC1=NC=CN1C GIWQSPITLQVMSG-UHFFFAOYSA-N 0.000 claims description 36
- 238000005406 washing Methods 0.000 claims description 32
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 28
- 229910017604 nitric acid Inorganic materials 0.000 claims description 28
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 27
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 claims description 27
- 229910001981 cobalt nitrate Inorganic materials 0.000 claims description 27
- 239000008367 deionised water Substances 0.000 claims description 27
- 229910021641 deionized water Inorganic materials 0.000 claims description 27
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 19
- 239000012153 distilled water Substances 0.000 claims description 18
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 18
- 150000001868 cobalt Chemical class 0.000 claims description 16
- 238000003756 stirring Methods 0.000 claims description 16
- 239000000725 suspension Substances 0.000 claims description 15
- 238000001035 drying Methods 0.000 claims description 14
- 235000005811 Viola adunca Nutrition 0.000 claims description 13
- 240000009038 Viola odorata Species 0.000 claims description 13
- 235000013487 Viola odorata Nutrition 0.000 claims description 13
- 235000002254 Viola papilionacea Nutrition 0.000 claims description 13
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 238000001816 cooling Methods 0.000 claims description 9
- 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 claims description 8
- 230000003197 catalytic effect Effects 0.000 abstract description 19
- 239000002086 nanomaterial Substances 0.000 abstract description 4
- 238000006555 catalytic reaction Methods 0.000 abstract description 2
- 238000001075 voltammogram Methods 0.000 description 16
- 239000003792 electrolyte Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 9
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 8
- 229910002804 graphite Inorganic materials 0.000 description 8
- 239000010439 graphite Substances 0.000 description 8
- 229910000474 mercury oxide Inorganic materials 0.000 description 8
- UKWHYYKOEPRTIC-UHFFFAOYSA-N mercury(ii) oxide Chemical compound [Hg]=O UKWHYYKOEPRTIC-UHFFFAOYSA-N 0.000 description 8
- 230000009286 beneficial effect Effects 0.000 description 7
- 239000012621 metal-organic framework Substances 0.000 description 7
- 238000002848 electrochemical method Methods 0.000 description 5
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 239000010411 electrocatalyst Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- 238000004832 voltammetry Methods 0.000 description 3
- 238000000970 chrono-amperometry Methods 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910000000 metal hydroxide Inorganic materials 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000010301 surface-oxidation reaction Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 230000036962 time dependent Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910000314 transition metal oxide Inorganic materials 0.000 description 2
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000003064 anti-oxidating effect Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000007809 chemical reaction catalyst Substances 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910001429 cobalt ion Inorganic materials 0.000 description 1
- XLJKHNWPARRRJB-UHFFFAOYSA-N cobalt(2+) Chemical compound [Co+2] XLJKHNWPARRRJB-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
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- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 125000005842 heteroatom Chemical group 0.000 description 1
- 238000007210 heterogeneous catalysis Methods 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 239000003446 ligand Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000003760 magnetic stirring Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
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- 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
- C25B1/02—Hydrogen or oxygen
- C25B1/04—Hydrogen or oxygen by electrolysis of water
-
- 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
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
- B01J31/28—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of the platinum group metals, iron group metals or copper
-
- B01J35/60—
-
- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
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- 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
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- 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
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- 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
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Abstract
A preparation method and application of an iron-modified cobaltosic oxide nanosheet array electrode belong to the field of electrochemical catalysis and energy, and particularly relate to a preparation method and application of an electrode. The invention aims to solve the problem that the existing nano material has low catalytic performance in the oxygen evolution reaction under the severe alkaline condition. The method comprises the following steps: firstly, processing carbon cloth; secondly, preparing a solution; thirdly, soaking; fourthly, anion etching; and fifthly, annealing treatment is carried out, and the cobaltosic oxide nanosheet array electrode and the iron-modified cobaltosic oxide nanosheet array electrode are obtained. An iron-modified cobaltosic oxide nanosheet array electrode is used for catalyzing an electrolytic water oxygen evolution reaction in an alkaline environment. The invention can obtain the iron-modified cobaltosic oxide nanosheet array electrode.
Description
Technical Field
The invention belongs to the field of electrochemical catalysis and energy, and particularly relates to a preparation method and application of an electrode.
Background
Due to environmental pollution caused by fossil fuels and increased energy demand, it is important to find environmentally friendly renewable energy sources. Among the numerous alternative energy sources, hydrogen is considered promising as an alternative to carbon-based fossil energy in the future due to its high energy density and carbon-free characteristics. The water electrolysis is an effective mode for large-scale hydrogen production, in the process, the water is the only raw material and the only byproduct, the production mode is environment-friendly, and the purity of the produced hydrogen is high. The water electrolysis process includes two half-pole reactions, namely a cathodic hydrogen evolution reaction and an anodic oxygen evolution reaction. However, the hydrolysis process is limited by the kinetically slow oxygen evolution reaction. The oxygen evolution reaction is a four-electron transfer process involving the cleavage of oxygen-hydrogen bonds and the formation of oxygen-oxygen bonds, with a theoretical limit of 1.23 volts. Therefore, exploring and designing a high-efficiency oxygen evolution reaction electrocatalyst has important significance for reducing overpotential and improving the energy efficiency of the whole process. Noble metal base (ruthenium base or iridium base) is still the mainstream high-efficiency oxygen evolution reaction catalyst at present. However, the low natural storage capacity, poor stability and high cost limit the large-scale application of the noble metal-based materials. Therefore, the development of the oxygen evolution catalytic material which is free of noble metal and is efficient and stable is of great significance. Wherein the transition metal oxide/hydroxide exhibits high efficiency oxygen evolution reaction electrocatalytic activity. In addition to chemical composition, the structure of the electrocatalyst is also an important factor affecting catalytic performance. Two-dimensional transition metal oxides/hydroxides, while exhibiting good oxygen evolution performance, most lack favorable porous characteristics. In order to make a two-dimensional material porous, it is important to develop a surface chemical conditioning method.
In recent years, more and more nano materials designed and synthesized by using a metal organic framework as a template exist. The metal organic framework is a rapidly developed porous material, is formed by reacting an organic connector with metal ions or ion clusters, and has wide application in the fields of heterogeneous catalysis, energy storage, conversion and the like due to chemical and structural diversity. The metal organic framework material has the characteristics of ordered structure, adjustable ligand, large surface area and more metal sites, so that the metal organic framework material has high active site density. Metal organic frameworks are unstable in water, especially under acidic and basic conditions, but provide an ideal template for designing a variety of electrode materials. A common conversion is to anneal the material in different gas atmospheres to incorporate non-metallic heteroatoms, such as porous metal oxides, carbides, nitrides or composites thereof. This process is accompanied by the creation of porosity due to the evaporation of organic substances. It is desirable that the basic structure and morphology of the resulting material be well maintained. However, the nano material designed and synthesized by taking the metal organic framework as the template has low catalytic performance of oxygen evolution reaction under the severe alkaline condition, and the current density reaches 10mA/cm2Most of the oxygen evolution electrocatalyst reported so far have overpotentials greater than 295 mV.
Disclosure of Invention
The invention aims to solve the problem that the catalytic performance of the existing nano material in the oxygen evolution reaction under the severe alkaline condition is low, and provides a preparation method and application of an iron-modified cobaltosic oxide nanosheet array electrode.
A preparation method of an iron-modified cobaltosic oxide nanosheet array electrode is completed according to the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the inner liner of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into a baking oven with the temperature of 95-105 ℃ for 2-4 h to obtain the treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-4 times, and then washing the treated carbon cloth with distilled water for 2-4 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 30 mmol/L-50 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 30 mmol/L-50 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 3-5 h at room temperature, taking out the carbon cloth, washing for 3-5 times by using distilled water, and finally drying for 8-10 h at the temperature of 50-70 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 1 g/L-5 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring at a stirring speed of 50-70 r/min for reaction for 1-3 h, taking out the carbon cloth, washing with deionized water for 3-5 times, and drying at a temperature of 50-70 ℃ for 8-10 h to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array modified by iron in a tubular furnace, heating the tubular furnace to 300-400 ℃ at a heating rate of 1.5-2.5 ℃/min, annealing at 300-400 ℃ for 1.5-2.5 h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode.
In the further step I, the mass fraction of the concentrated nitric acid is 67-69%.
The concentration of the cobalt nitrate solution in the second step is 35 mmol/L-40 mmol/L.
The concentration of the 1, 2-dimethyl imidazole solution in the second step is 35 mmol/L-40 mmol/L.
The concentration of the potassium ferricyanide solution in the fourth step is 2 g/L-2.5 g/L.
Adding concentrated nitric acid into the lining of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into an oven with the temperature of 95-100 ℃ for 2-3 h to obtain the treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-3 times, and then washing the treated carbon cloth with distilled water for 2-3 times to obtain the carbon cloth with the surface oxide layer removed; and (4) storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol.
And in the third step, the carbon cloth which is stored in the absolute ethyl alcohol and is removed of the surface oxidation layer is taken out and then is immersed into the blue-violet suspension, the reaction is carried out for 3 to 4 hours at room temperature, then the carbon cloth is taken out and is washed for 3 to 4 times by using distilled water, and finally the carbon cloth is dried for 8 to 9 hours at the temperature of 50 to 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array.
And in the fourth step, the carbon cloth with the cobalt-based metal organic framework nanosheet array growing is immersed into a potassium ferricyanide solution, then the magnetic stirring reaction is carried out for 1h to 2h at the stirring speed of 50r/min to 70r/min, then the carbon cloth is taken out, the carbon cloth is washed for 3 times to 4 times by using deionized water, and then the carbon cloth is dried for 8h to 9h at the temperature of 50 ℃ to 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array growing iron modification.
And fifthly, putting the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array in a tubular furnace, heating the tubular furnace to 300-350 ℃ at a heating rate of 1.5-2 ℃/min, annealing at 300-350 ℃ for 1.5-2 h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode.
An iron-modified cobaltosic oxide nanosheet array electrode is used for catalyzing an electrolytic water oxygen evolution reaction in an alkaline environment.
The principle and the advantages of the invention are as follows:
the carbon cloth used in the invention is a purchased commercialized carbon cloth, and has corrosion resistance, conductivity, flexibility and an integrated three-dimensional structure; firstly, treating an anti-oxidation coating on the surface of carbon cloth by using concentrated nitric acid, then enabling cobalt ions and 1, 2-dimethyl imidazole to generate a coordination reaction, depositing the coordination reaction on a carbon cloth substrate based on a normal-temperature liquid phase deposition reaction principle, then reacting the synthesized cobalt-based metal organic framework nanosheet array with iron cyanate ions, and etching to obtain an iron-modified cobalt-based metal organic framework nanosheet array; finally, the iron-modified cobaltosic oxide nanosheet array electrode is obtained through annealing treatment, the iron modification greatly improves the electron transfer efficiency, improves the utilization of active sites, and greatly improves the catalytic performance; the iron-modified cobaltosic oxide nanosheet array electrode prepared by the method directly grows on a carbon cloth substrate, so that the stability of a catalyst is facilitated, and the synergistic effect of the porous structure and the nanosheet array is beneficial to the permeation of electrolyte, ion transfer and efficient utilization of active sites; the method can realize the iron-modified cobaltosic oxide nanosheet array electrode based on the carbon cloth, and is beneficial to designing and constructing the heteroatom-doped or modified nano array material by taking the metal organic framework as the template to be widely applied to the energy-related field.
The invention has the advantages that:
(1) the cost is controllable: the materials required by the invention are cheap and easily available, and only one piece of commercialized carbon cloth and a certain amount of concentrated nitric acid, cobalt nitrate hexahydrate, potassium ferricyanide and 1, 2-dimethyl imidazole are needed;
(2) the operation is simple: although a certain temperature environment needs to be provided for the treatment and high-temperature annealing of the carbon cloth, the whole synthesis process does not need high voltage, an electric field, a strict gas environment and the like;
(3) and high catalytic activity: under the conditions of low cost and simple operation, the prepared iron-modified cobaltosic oxide nanosheet array electrode still has good catalytic performance, obviously provides the catalytic performance of oxygen evolution reaction under severe alkaline conditions, and when the current density of the oxygen evolution reaction reaches 10mA/cm2And 20mA/cm2During the process, the overpotential is only 290 mV-295 mV and 310 mV-315 mV respectively, and the tafel slope is as low as 74.7mV/dev, so that the good oxygen evolution reaction performance can be attributed to good conductivity generated by modification of iron and efficient utilization of catalytic active sites, and abundant nanopores generated on the nanosheets, open spaces among the nanosheets, and the synergistic effect of the nanosheet array and the conductive substrate are beneficial to permeation of electrolyte and diffusion of oxygen, and are beneficial to improving the stability of the catalyst.
The invention can obtain the iron-modified cobaltosic oxide nanosheet array electrode.
Drawings
Fig. 1 is an SEM image of an iron-modified cobaltosic oxide nanosheet array electrode prepared in example two;
fig. 2 is a linear scanning voltammogram of an iron-modified cobaltosic oxide nanosheet array electrode prepared under different concentrations of ferricyanate ions, wherein 1 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 1.25g/L potassium ferricyanide solution in example one, 2 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 2.5g/L potassium ferricyanide solution in example two, and 3 is a linear voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 5g/L potassium ferricyanide solution in example three;
fig. 3 is a linear scanning voltammogram, in which 1 is a linear scanning voltammogram of the carbon cloth with the surface oxide layer removed obtained in the first step of the embodiment, 2 is a linear scanning voltammogram of the cobaltosic oxide nanosheet array electrode obtained in the fifth step of the embodiment, and 3 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode obtained in the fifth step of the embodiment;
FIG. 4 is a time-dependent voltage curve of the iron-modified cobaltosic oxide nanosheet array electrode obtained in the second step five of the example, in which the current density of the curve 1 is 10mA/cm2The current density of curve 2 was 20mA/cm2。
Detailed Description
The first embodiment is as follows: the embodiment is a preparation method of an iron-modified cobaltosic oxide nanosheet array electrode, which is completed by the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the inner liner of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into a baking oven with the temperature of 95-105 ℃ for 2-4 h to obtain the treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-4 times, and then washing the treated carbon cloth with distilled water for 2-4 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 30 mmol/L-50 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 30 mmol/L-50 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 3-5 h at room temperature, taking out the carbon cloth, washing for 3-5 times by using distilled water, and finally drying for 8-10 h at the temperature of 50-70 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 1 g/L-5 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring at a stirring speed of 50-70 r/min for reaction for 1-3 h, taking out the carbon cloth, washing with deionized water for 3-5 times, and drying at a temperature of 50-70 ℃ for 8-10 h to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array modified by iron in a tubular furnace, heating the tubular furnace to 300-400 ℃ at a heating rate of 1.5-2.5 ℃/min, annealing at 300-400 ℃ for 1.5-2.5 h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode.
The advantages of this embodiment:
(1) the cost is controllable: the materials required by the embodiment are cheap and easily available, and only one piece of commercialized carbon cloth and a certain amount of concentrated nitric acid, cobalt nitrate hexahydrate, potassium ferricyanide and 1, 2-dimethyl imidazole are required;
(2) the operation is simple: although a certain temperature environment needs to be provided for the treatment and high-temperature annealing of the carbon cloth, the whole synthesis process does not need high voltage, an electric field, a strict gas environment and the like;
(3) and high catalytic activity: under the conditions of low cost and simple operation, the prepared iron-modified cobaltosic oxide nanosheet array electrode prepared by the embodiment still has good catalytic performance, obviously provides catalytic performance of oxygen evolution reaction under severe alkaline conditions, and when the current density of the oxygen evolution reaction reaches 10mA/cm2And 20mA/cm2During the process, the overpotential is only 290 mV-295 mV and 310 mV-315 mV respectively, and the tafel slope is as low as 74.7mV/dev, so that the good oxygen evolution reaction performance can be attributed to good conductivity generated by modification of iron and efficient utilization of catalytic active sites, and abundant nanopores generated on the nanosheets, open spaces among the nanosheets, and the synergistic effect of the nanosheet array and the conductive substrate are beneficial to permeation of electrolyte and diffusion of oxygen, and are beneficial to improving the stability of the catalyst.
The present embodiment can obtain an iron-modified cobaltosic oxide nanosheet array electrode.
The second embodiment is as follows: the present embodiment differs from the present embodiment in that: the mass fraction of the concentrated nitric acid in the step one is 67-69%. Other steps are the same as in the first embodiment.
The third concrete implementation mode: the present embodiment differs from the first or second embodiment in that: the mass fraction of the concentrated nitric acid in the step one is 68%. The other steps are the same as in the first or second embodiment.
The fourth concrete implementation mode: the difference between this embodiment and one of the first to third embodiments is as follows: and the concentration of the cobalt nitrate solution in the second step is 35 mmol/L-40 mmol/L. The other steps are the same as those in the first to third embodiments.
The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: the concentration of the 1, 2-dimethyl imidazole solution in the second step is 35 mmol/L-40 mmol/L. The other steps are the same as those in the first to fourth embodiments.
The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is as follows: and the concentration of the potassium ferricyanide solution in the fourth step is 2 g/L-2.5 g/L. The other steps are the same as those in the first to fifth embodiments.
The seventh embodiment: the difference between this embodiment and one of the first to sixth embodiments is: and the concentration of the potassium ferricyanide solution in the fourth step is 1.25 g/L. The other steps are the same as those in the first to sixth embodiments.
The specific implementation mode is eight: the difference between this embodiment and one of the first to seventh embodiments is: adding concentrated nitric acid into the lining of a hydrothermal reaction kettle, immersing carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into an oven with the temperature of 95-100 ℃ for 2-3 h to obtain treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-3 times, and then washing the treated carbon cloth with distilled water for 2-3 times to obtain the carbon cloth with the surface oxide layer removed; and (4) storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol. The other steps are the same as those in the first to seventh embodiments.
The specific implementation method nine: the difference between this embodiment and the first to eighth embodiments is: and step three, taking out the carbon cloth which is stored in the absolute ethyl alcohol and is removed of the surface oxidation layer, immersing the carbon cloth into the blue-purple suspension, reacting for 3-4 h at room temperature, taking out the carbon cloth, washing for 3-4 times by using distilled water, and finally drying for 8-9 h at the temperature of 50-60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array. The other steps are the same as those in the first to eighth embodiments.
The detailed implementation mode is ten: the difference between this embodiment and one of the first to ninth embodiments is as follows: and step four, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring at a stirring speed of 50-70 r/min for reaction for 1-2 h, taking out the carbon cloth, washing with deionized water for 3-4 times, and drying at a temperature of 50-60 ℃ for 8-9 h to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array. The other steps are the same as those in the first to ninth embodiments.
The concrete implementation mode eleven: the present embodiment differs from the first to tenth embodiments in that: and fifthly, putting the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array in a tubular furnace, heating the tubular furnace to 300-350 ℃ at a heating rate of 1.5-2 ℃/min, annealing at 300-350 ℃ for 1.5-2 h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode. The other steps are the same as those in the first to tenth embodiments.
The specific implementation mode twelve: the present embodiment differs from the first to eleventh embodiments in that: and fifthly, putting the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array in a tubular furnace, heating the tubular furnace to 350 ℃ at the heating rate of 2 ℃/min, annealing at 350 ℃ for 2h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode. The other steps are the same as in embodiments one to eleven.
The specific implementation mode is thirteen: the embodiment is that the iron-modified cobaltosic oxide nanosheet array electrode is used for catalyzing the electrolytic water oxygen evolution reaction in the alkaline environment.
The following examples were used to demonstrate the beneficial effects of the present invention:
the first embodiment is as follows: a preparation method of an iron-modified cobaltosic oxide nanosheet array electrode is completed according to the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the lining of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into an oven with the temperature of 100 ℃ for 3 hours to obtain treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 3 times, and then washing the treated carbon cloth with distilled water for 3 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
the mass fraction of the concentrated nitric acid in the step one is 68 percent;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 40 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 40 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 4 hours at room temperature, taking out the carbon cloth, washing for 4 times by using distilled water, and finally drying for 8 hours at the temperature of 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 1.25 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring the carbon cloth at a stirring speed of 60r/min for reaction for 2 hours, taking out the carbon cloth, washing the carbon cloth with deionized water for 4 times, and drying the carbon cloth at a temperature of 60 ℃ for 8 hours to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array and the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array into a tubular furnace, heating the tubular furnace to 350 ℃ at a heating rate of 2 ℃/min, annealing at 350 ℃ for 2h, and naturally cooling to room temperature to obtain the cobaltosic oxide nanosheet array electrode and the iron-modified cobaltosic oxide nanosheet array electrode.
The length of the carbon cloth described in the first step of the example was 0.5cm x 0.5 cm.
Example two: a preparation method of an iron-modified cobaltosic oxide nanosheet array electrode is completed according to the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the lining of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into an oven with the temperature of 100 ℃ for 3 hours to obtain treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 3 times, and then washing the treated carbon cloth with distilled water for 3 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
the mass fraction of the concentrated nitric acid in the step one is 68 percent;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 40 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 40 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 4 hours at room temperature, taking out the carbon cloth, washing for 4 times by using distilled water, and finally drying for 8 hours at the temperature of 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 2.5 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring the carbon cloth at a stirring speed of 60r/min for reaction for 2 hours, taking out the carbon cloth, washing the carbon cloth with deionized water for 4 times, and drying the carbon cloth at a temperature of 60 ℃ for 8 hours to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array and the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array into a tubular furnace, heating the tubular furnace to 350 ℃ at a heating rate of 2 ℃/min, annealing at 350 ℃ for 2h, and naturally cooling to room temperature to obtain the cobaltosic oxide nanosheet array electrode and the iron-modified cobaltosic oxide nanosheet array electrode.
The length of the carbon cloth described in the first two steps of the example was 0.5cm x 0.5 cm.
Example three: a preparation method of an iron-modified cobaltosic oxide nanosheet array electrode is completed according to the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the lining of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into an oven with the temperature of 100 ℃ for 3 hours to obtain treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 3 times, and then washing the treated carbon cloth with distilled water for 3 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
the mass fraction of the concentrated nitric acid in the step one is 68 percent;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 40 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 40 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 4 hours at room temperature, taking out the carbon cloth, washing for 4 times by using distilled water, and finally drying for 8 hours at the temperature of 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 5 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring the carbon cloth at a stirring speed of 60r/min for reaction for 2 hours, taking out the carbon cloth, washing the carbon cloth with deionized water for 4 times, and drying the carbon cloth at a temperature of 60 ℃ for 8 hours to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array and the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array into a tubular furnace, heating the tubular furnace to 350 ℃ at a heating rate of 2 ℃/min, annealing at 350 ℃ for 2h, and naturally cooling to room temperature to obtain the cobaltosic oxide nanosheet array electrode and the iron-modified cobaltosic oxide nanosheet array electrode.
The length of the carbon cloth described in the first three steps of the example was 0.5cm × 0.5 cm.
Fig. 1 is an SEM image of an iron-modified cobaltosic oxide nanosheet array electrode prepared in example two;
as can be seen from fig. 1, the microstructure of the iron-modified cobaltosic oxide nanosheet array electrode prepared in example two is a uniform and regular nanosheet array.
X-ray photoelectron spectroscopy showed that divalent cobalt, trivalent cobalt and trivalent iron coexisted in the iron-modified cobaltosic oxide nanosheet array electrode prepared in example two.
Testing the influence of the concentration of iron cyanate ions on the catalytic performance of carbon cloth of a cobalt-based metal organic framework nanosheet array which grows with iron modification:
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, an iron-modified cobaltosic oxide nanosheet array electrode prepared in the first embodiment is used as a working electrode, an electrolyte is a potassium hydroxide solution with the concentration of 1.0mol/L, the three electrodes are respectively connected with an electrochemical workstation, and electrochemical data are tested, as shown in 1 in fig. 2;
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, the iron-modified cobaltosic oxide nanosheet array electrode prepared in the second embodiment is used as a working electrode, an electrolyte is a potassium hydroxide solution with the concentration of 1.0mol/L, the three electrodes are respectively connected with an electrochemical workstation, and electrochemical data are tested, as shown in 2 in fig. 2;
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, an iron-modified cobaltosic oxide nanosheet array electrode prepared in the third embodiment is used as a working electrode, an electrolyte is a potassium hydroxide solution with the concentration of 1.0mol/L, the three electrodes are respectively connected with an electrochemical workstation, and electrochemical data are tested, as shown in 3 in fig. 2;
fig. 2 is a linear scanning voltammogram of an iron-modified cobaltosic oxide nanosheet array electrode prepared under different concentrations of ferricyanate ions, wherein 1 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 1.25g/L potassium ferricyanide solution in example one, 2 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 2.5g/L potassium ferricyanide solution in example two, and 3 is a linear voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode prepared under a 5g/L potassium ferricyanide solution in example three;
as can be seen from fig. 2, the cobalt-based metal organic framework nanosheet array is etched with different concentrations of potassium ferricyanide solution, and the catalytic performance of the final product is basically the same, which indicates that the concentration of ferricyanide ions has little influence on the catalytic performance of the carbon cloth on which the cobalt-based metal organic framework nanosheet array modified by iron grows.
Electrolytic water oxygen evolution reaction test:
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, carbon cloth with a surface oxide layer removed, which is obtained in the first step of the second step, is used as a working electrode, and an electrolyte is a potassium hydroxide solution with the concentration of 1.0 mol/L; connecting the three electrodes with an electrochemical workstation respectively, and performing electrochemical measurement by using linear voltammetry, as shown in 1 in fig. 3;
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, a cobaltosic oxide nanosheet array electrode obtained in the fifth step of the embodiment is used as a working electrode, and an electrolyte is a potassium hydroxide solution with the concentration of 1.0 mol/L; connecting the three electrodes with an electrochemical workstation respectively, and performing electrochemical measurement by using linear voltammetry, as shown in 2 in fig. 3;
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, the iron-modified cobaltosic oxide nanosheet array electrode obtained in the second step five of the embodiment is used as a working electrode, and the electrolyte is a potassium hydroxide solution with the concentration of 1.0 mol/L; connecting the three electrodes with an electrochemical workstation respectively, and performing electrochemical measurement by using linear voltammetry, as shown in 3 in fig. 3;
fig. 3 is a linear scanning voltammogram, in which 1 is a linear scanning voltammogram of the carbon cloth with the surface oxide layer removed obtained in the first step of the embodiment, 2 is a linear scanning voltammogram of the cobaltosic oxide nanosheet array electrode obtained in the fifth step of the embodiment, and 3 is a linear scanning voltammogram of the iron-modified cobaltosic oxide nanosheet array electrode obtained in the fifth step of the embodiment;
as can be seen from fig. 3, the oxygen evolution catalytic activity of the iron-modified cobaltosic oxide nanosheet array electrode is obviously improved compared with that of the cobaltosic oxide nanosheet array electrode and the carbon cloth with the surface oxide layer removed (the carbon cloth with the surface oxide layer removed obtained in the first step of the embodiment), and the current density reaches 10mA/cm2When the overvoltage of the iron-modified cobaltosic oxide nanosheet array electrode is 290mV, the overvoltage of the cobaltosic oxide nanosheet array electrode is 360mV, and the overvoltage of the carbon cloth is 435 mV. When the current density reaches 20mA/cm2When the electrode is used, the overpotential of the iron-modified cobaltosic oxide nanosheet array electrode is 310 mV.
In a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, the iron-modified cobaltosic oxide nanosheet array electrode obtained in the second step five of the embodiment is used as a working electrode, and the electrolyte is a potassium hydroxide solution with the concentration of 1.0 mol/L; connecting the three electrodes with an electrochemical workstation respectively, and performing electrochemical measurement by using a chronoamperometry at a current density of 10mA/cm2As shown at 1 in fig. 4;
in a standard three-electrode electrolytic cell, a mercury oxide electrode is used as a reference electrode, a graphite rod electrode is used as a counter electrode, the iron-modified cobaltosic oxide nanosheet array electrode obtained in the second step five of the embodiment is used as a working electrode, and the electrolyte is a potassium hydroxide solution with the concentration of 1.0 mol/L; connecting the three electrodes with an electrochemical workstation respectively, and performing electrochemical measurement by using a chronoamperometry at a current density of 20mA/cm2As shown at 2 in FIG. 4；
FIG. 4 is a time-dependent voltage curve of the iron-modified cobaltosic oxide nanosheet array electrode obtained in the second step five of the example, in which the current density of the curve 1 is 10mA/cm2The current density of curve 2 was 20mA/cm2。
As can be seen from FIG. 4, when the current density was 10mA/cm2The overpotential increased only 5mV over 25 hours. When the current density is 20mA/cm2In time, the overpotential increased by 17mV in about 14 hours. The iron-modified cobaltosic oxide nanosheet array electrode obtained in the fifth step of the example has good stability in the catalytic oxygen evolution reaction.
Claims (9)
1. A preparation method of an iron-modified cobaltosic oxide nanosheet array electrode is characterized in that the preparation method of the iron-modified cobaltosic oxide nanosheet array electrode is completed according to the following steps:
firstly, processing carbon cloth:
adding concentrated nitric acid into the inner liner of a hydrothermal reaction kettle, immersing the carbon cloth into the concentrated nitric acid, and putting the hydrothermal reaction kettle into a baking oven with the temperature of 95-105 ℃ for 2-4 h to obtain the treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-4 times, and then washing the treated carbon cloth with distilled water for 2-4 times to obtain the carbon cloth with the surface oxide layer removed; storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol;
secondly, preparing a solution:
firstly, dissolving cobalt nitrate hexahydrate into deionized water to obtain a cobalt nitrate solution;
the concentration of the cobalt nitrate solution in the second step is 30 mmol/L-50 mmol/L;
dissolving 1, 2-dimethyl imidazole in deionized water to obtain a 1, 2-dimethyl imidazole solution;
the concentration of the 1, 2-dimethyl imidazole solution in the second step is 30 mmol/L-50 mmol/L;
thirdly, adding the 1, 2-dimethyl imidazole solution into the cobalt nitrate solution to obtain blue-violet suspension;
the volume ratio of the 1, 2-dimethyl imidazole solution to the cobalt nitrate solution in the second step is 1: 1;
thirdly, soaking:
taking out the carbon cloth which is stored in absolute ethyl alcohol and is removed of the surface oxide layer, immersing the carbon cloth into a blue-violet suspension, reacting for 3-5 h at room temperature, taking out the carbon cloth, washing for 3-5 times by using distilled water, and finally drying for 8-10 h at the temperature of 50-70 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array;
fourthly, anion etching:
dissolving potassium ferricyanide in deionized water to obtain a potassium ferricyanide solution;
the concentration of the potassium ferricyanide solution in the fourth step is 2 g/L-2.5 g/L;
secondly, immersing the carbon cloth with the cobalt-based metal organic framework nanosheet array in a potassium ferricyanide solution, magnetically stirring at a stirring speed of 50-70 r/min for reaction for 1-3 h, taking out the carbon cloth, washing with deionized water for 3-5 times, and drying at a temperature of 50-70 ℃ for 8-10 h to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array;
fifthly, annealing treatment:
putting the carbon cloth with the cobalt-based metal organic framework nanosheet array modified by iron in a tubular furnace, heating the tubular furnace to 300-400 ℃ at a heating rate of 1.5-2.5 ℃/min, annealing at 300-400 ℃ for 1.5-2.5 h, and naturally cooling to room temperature to obtain the iron-modified cobaltosic oxide nanosheet array electrode.
2. The method for preparing an iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, wherein the concentrated nitric acid in the first step is 67-69% by weight.
3. The method for preparing an iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, wherein the concentration of the cobalt nitrate solution in the second r is 35 to 40 mmol/L.
4. The method for preparing an iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, wherein the concentration of the 1, 2-dimethylimidazole solution in the second step is 35mmol/L to 40 mmol/L.
5. The preparation method of the iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, wherein in the first step, concentrated nitric acid is added into the lining of a hydrothermal reaction kettle, then a carbon cloth is immersed into the concentrated nitric acid, and then the hydrothermal reaction kettle is placed into an oven with the temperature of 95-100 ℃ for 2-3 h to obtain the treated carbon cloth; washing the treated carbon cloth with absolute ethyl alcohol for 2-3 times, and then washing the treated carbon cloth with distilled water for 2-3 times to obtain the carbon cloth with the surface oxide layer removed; and (4) storing the carbon cloth with the surface oxide layer removed in absolute ethyl alcohol.
6. The preparation method of the iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, characterized in that in the third step, the carbon cloth which is stored in absolute ethyl alcohol and has the surface oxide layer removed is taken out and then immersed in a bluish-purple suspension, then the carbon cloth is reacted for 3h to 4h at room temperature, then the carbon cloth is taken out, the carbon cloth is washed for 3 to 4 times by using distilled water, and finally the carbon cloth with the cobalt-based metal organic framework nanosheet array grown thereon is dried for 8h to 9h at the temperature of 50 ℃ to 60 ℃ to obtain the carbon cloth with the cobalt-based metal organic framework nanosheet array grown thereon.
7. The preparation method of the iron-modified cobaltosic oxide nanosheet array electrode as claimed in claim 1, wherein in step four, the carbon cloth with the cobalt-based metal organic framework nanosheet array grown is immersed in the potassium ferricyanide solution, then the carbon cloth is magnetically stirred at a stirring speed of 50 r/min-70 r/min for reaction for 1 h-2 h, then the carbon cloth is taken out, washed with deionized water for 3-4 times, and then dried at a temperature of 50-60 ℃ for 8 h-9 h to obtain the carbon cloth with the iron-modified cobalt-based metal organic framework nanosheet array grown.
8. The preparation method of an iron-modified cobaltosic oxide nanosheet array electrode according to claim 1, wherein in step five, the carbon cloth on which the iron-modified cobalt-based metal organic framework nanosheet array is grown is placed in a tubular furnace, the tubular furnace is heated to 300-350 ℃ at a heating rate of 1.5-2 ℃/min, then the tubular furnace is annealed for 1.5-2 h at the temperature of 300-350 ℃, and then the tubular furnace is naturally cooled to room temperature, so that the iron-modified cobaltosic oxide nanosheet array electrode is obtained.
9. The use of an iron-modified cobaltosic oxide nanosheet array electrode of claim 1, wherein an iron-modified cobaltosic oxide nanosheet array electrode is used to catalyze an electrolytic water-out oxygen reaction in an alkaline environment.
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| CN106025302A (en) * | 2016-07-18 | 2016-10-12 | 天津理工大学 | Single-cell-thickness nano porous cobalt oxide nanosheet array electrocatalytic material |
| CN106048650B (en) * | 2016-08-04 | 2018-06-12 | 浙江大学 | The preparation method of 3D porous electrodes and its application in electrochemistry evolving hydrogen reaction |
| CN108346522B (en) * | 2018-03-28 | 2020-01-10 | 安徽师范大学 | Cobaltosic oxide hierarchical structure nano array material, preparation method and application thereof |
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