CN116364961B - Oxygen reduction catalyst, preparation method thereof and fuel cell - Google Patents
Oxygen reduction catalyst, preparation method thereof and fuel cell Download PDFInfo
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- CN116364961B CN116364961B CN202310066934.4A CN202310066934A CN116364961B CN 116364961 B CN116364961 B CN 116364961B CN 202310066934 A CN202310066934 A CN 202310066934A CN 116364961 B CN116364961 B CN 116364961B
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- 230000009467 reduction Effects 0.000 title claims abstract description 171
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 164
- 239000001301 oxygen Substances 0.000 title claims abstract description 164
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 164
- 239000003054 catalyst Substances 0.000 title claims abstract description 136
- 239000000446 fuel Substances 0.000 title abstract description 18
- 238000002360 preparation method Methods 0.000 title abstract description 12
- 239000000956 alloy Substances 0.000 claims abstract description 127
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 125
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 103
- 229910052751 metal Inorganic materials 0.000 claims abstract description 48
- 239000002184 metal Substances 0.000 claims abstract description 44
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 38
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 37
- 150000003624 transition metals Chemical class 0.000 claims abstract description 34
- 239000002245 particle Substances 0.000 claims abstract description 13
- 239000011258 core-shell material Substances 0.000 claims abstract description 9
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 4
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 4
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 90
- 239000002243 precursor Substances 0.000 claims description 86
- 239000012018 catalyst precursor Substances 0.000 claims description 46
- 229910052757 nitrogen Inorganic materials 0.000 claims description 44
- 239000000843 powder Substances 0.000 claims description 35
- 239000001257 hydrogen Substances 0.000 claims description 33
- 229910052739 hydrogen Inorganic materials 0.000 claims description 33
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- 238000009777 vacuum freeze-drying Methods 0.000 claims description 21
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- 229910052718 tin Inorganic materials 0.000 claims description 10
- 229910052720 vanadium Inorganic materials 0.000 claims description 10
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 claims description 9
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 claims description 9
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims description 9
- 229910002651 NO3 Inorganic materials 0.000 claims description 9
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 9
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 claims description 9
- 150000004820 halides Chemical class 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- KLFRPGNCEJNEKU-FDGPNNRMSA-L (z)-4-oxopent-2-en-2-olate;platinum(2+) Chemical compound [Pt+2].C\C([O-])=C\C(C)=O.C\C([O-])=C\C(C)=O KLFRPGNCEJNEKU-FDGPNNRMSA-L 0.000 claims description 8
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- 150000003057 platinum Chemical class 0.000 claims description 7
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- 239000002041 carbon nanotube Substances 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 3
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- 230000003197 catalytic effect Effects 0.000 abstract description 8
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- 239000012528 membrane Substances 0.000 description 6
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 5
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- 229910021641 deionized water Inorganic materials 0.000 description 5
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- 230000000694 effects Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 235000015393 sodium molybdate Nutrition 0.000 description 3
- 239000011684 sodium molybdate Substances 0.000 description 3
- TVXXNOYZHKPKGW-UHFFFAOYSA-N sodium molybdate (anhydrous) Chemical compound [Na+].[Na+].[O-][Mo]([O-])(=O)=O TVXXNOYZHKPKGW-UHFFFAOYSA-N 0.000 description 3
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
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- 238000002386 leaching Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
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- -1 transition metal salt Chemical class 0.000 description 2
- 229920000557 Nafion® Polymers 0.000 description 1
- DSVGQVZAZSZEEX-UHFFFAOYSA-N [C].[Pt] Chemical compound [C].[Pt] DSVGQVZAZSZEEX-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000000861 blow drying Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
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Classifications
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- 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
- H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
- H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
-
- 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
- H01M4/8647—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites
- H01M4/8657—Inert electrodes with catalytic activity, e.g. for fuel cells consisting of more than one material, e.g. consisting of composites layered
-
- 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
- H01M4/88—Processes of manufacture
- H01M4/8825—Methods for deposition of the catalytic active composition
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Composite Materials (AREA)
- Manufacturing & Machinery (AREA)
- Catalysts (AREA)
Abstract
The application provides an oxygen reduction catalyst, a preparation method thereof and a fuel cell, and belongs to the technical field of fuel cells. The oxygen reduction catalyst comprises a carrier and active particles loaded on the carrier, wherein the active particles have a core-shell structure and comprise a high-entropy alloy core, a transition metal sub-shell coated on the high-entropy alloy core and a platinum-rich shell coated on the transition metal sub-shell, the platinum-rich shell comprises platinum metal and G metal, and the G metal comprises any one or more of Mo, au, W, hf and Ta. The oxygen reduction catalyst reduces the use amount of platinum, and can improve the utilization efficiency of platinum atoms on the premise of low platinum loading rate, thereby ensuring that the catalyst has higher catalytic activity of oxygen reduction reaction and improving the stability of the catalyst.
Description
Technical Field
The application relates to the technical field of fuel cells, in particular to an oxygen reduction catalyst, a preparation method thereof and a fuel cell.
Background
Proton exchange membrane fuel cells are one of the most promising energy sources for electric vehicles, and oxygen reduction (ORR) is an important cathode reaction in proton exchange membrane fuel cells (Proton exchange membrane fuel by the battery, PEMFC), but the kinetics of oxygen reduction is slower.
Pt/C catalysts are considered to be the most effective oxygen reduction catalysts, but Pt/C catalysts are high in cost, low in reserves and poor in stability, and there is still a need for improvement in mass production when fuel cell automobiles are used.
Disclosure of Invention
The application provides an oxygen reduction catalyst, a preparation method thereof and a fuel cell, which can ensure the catalytic activity of the oxygen reduction reaction of the catalyst and improve the stability of the catalyst on the premise of low platinum loading rate.
Embodiments of the present application are implemented as follows:
in a first aspect, the present examples provide an oxygen reduction catalyst comprising a support and active particles supported on the support, the active particles having a core-shell structure, the active particles comprising: the high-entropy alloy core, a transition metal sub-shell coated on the high-entropy alloy core, and a platinum-rich shell coated on the transition metal sub-shell, wherein the platinum-rich shell comprises platinum metal and G metal, and the G metal comprises any one or more of Mo, au, W, hf and Ta.
In the technical scheme, the high-entropy alloy core is positioned in the core-shell structure, the influence on the oxygen reduction catalytic activity of the catalyst is small, and the high-order high-entropy alloy core can ensure that strong alloy bonds are formed between internal alloys through strong interaction. The G metal can form strong G-M and G-Pt bonds with the transition metal sub-shell and the platinum-rich outer shell respectively, so that the outward precipitation of transition metal in the sub-shell in the reaction process is inhibited, the chemical adsorption of oxygen element in the reaction process is enhanced, and the adsorption of Pt to O is reduced. The oxygen reduction catalyst reduces the use amount of platinum, and platinum atoms are enriched on the outer surface layer of the structure, so that the utilization efficiency of the platinum atoms of the catalyst is improved on the premise of low platinum loading rate, the catalyst is ensured to have higher catalytic activity of oxygen reduction reaction, and the stability of the catalyst is improved.
With reference to the first aspect, in a first possible example of the first aspect of the present application, in the platinum-rich housing, the mass of the G metal is 1% to 5% of the mass of the platinum metal.
In the above example, when the mass of the G metal is 1% -5% of the mass of the platinum metal, when the core-shell structure is formed by heat treatment of the catalyst, a small amount of the G metal can preferentially occupy the edges and the peaks of the shell, which are easy to dissolve and precipitate transition metal in the reaction process, block the leaching path of the transition metal in the sub-shell, and enable the platinum metal to still maintain higher activity in the platinum-rich shell, thereby ensuring that the catalyst has higher catalytic activity for oxygen reduction reaction.
With reference to the first aspect, in a second possible example of the first aspect of the present application, the transition metal sub-shell includes M metal, and the M metal includes any one or more of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
With reference to the first aspect, in a third possible example of the first aspect of the present application, the high-entropy alloy core includes the following metal elements: fe. Cu, co, ni, al, mn, cr, V, ti and Sn.
Optionally, the mass ratio of the high-entropy alloy core to the carrier is 0.2-0.5:1.
Alternatively, the support is a carbon support.
Optionally, the carbon support comprises mesoporous carbon, hollow carbon spheres, carbon nanotubes, carbon black, graphitic carbon or graphene.
Alternatively, in the high-entropy alloy core, the atomic number of each metal element accounts for 5% -30% of the total atomic number of the high-entropy alloy.
In the above examples, the carbon support can mitigate agglomeration of alloy nanoparticles during high temperature ordering, enhancing conductivity during catalyst reactions.
With reference to the first aspect, in a fourth possible example of the first aspect of the present application, the mass ratio of the high-entropy alloy core to the platinum-rich shell is 1:1 to 5, and the mass ratio of the transition metal sub-shell to the platinum-rich shell is 1:1 to 5.
In a second aspect, the present application provides a method for preparing an oxygen reduction catalyst of the above embodiment, which includes: providing a high-entropy alloy core loaded on a carrier, mixing and dispersing a transition metal salt precursor, a G metal salt precursor, a platinum salt precursor, the high-entropy alloy core loaded on the carrier and a first solvent to prepare an oxygen reduction catalyst precursor, and then carrying out gas phase reduction on the oxygen reduction catalyst precursor to prepare the oxygen reduction catalyst.
Optionally, the salt precursor of the transition metal comprises any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salts of the M metal, which comprises any one or more of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
Optionally, the salt precursor of metal G includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate, and carbonyl salts of metal G.
Optionally, the platinum salt precursor comprises chloroplatinic acid salt and/or platinum acetylacetonate.
Optionally, the first solvent comprises water.
In the technical scheme, the preparation method of the oxygen reduction catalyst can simultaneously construct the transition metal sub-shell and the platinum-rich shell through gas phase reduction, and the G metal can promote the formation of the transition metal sub-shell and the platinum-rich shell.
With reference to the second aspect, in a first possible example of the second aspect of the present application, the step of preparing the oxygen reduction catalyst by gas phase reduction of the oxygen reduction catalyst precursor includes:
and reducing the oxygen reduction catalyst precursor for 0.5 to 3 hours at the temperature of between 500 and 900 ℃ in a mixed atmosphere of nitrogen and hydrogen.
Optionally, the volume ratio of nitrogen to hydrogen in the mixed atmosphere is 5:1-50:1.
With reference to the second aspect, in a second possible example of the second aspect of the present application, before the oxygen-reducing catalyst precursor is gas-phase reduced, the oxygen-reducing catalyst precursor is subjected to vacuum freeze-drying treatment to obtain oxygen-reducing catalyst precursor powder.
In the above example, the vacuum freeze-drying process can sublimate the first solvent in the oxygen reduction catalyst precursor to obtain the oxygen reduction catalyst precursor powder.
With reference to the second aspect, in a third possible example of the second aspect of the present application, the high-entropy alloy core supported on the carrier is prepared by:
and mixing and dispersing the carrier, the salt precursor of the high-entropy alloy and the second solvent to obtain a precursor of the high-entropy alloy core loaded on the carrier, and carrying out gas phase reduction on the precursor of the high-entropy alloy core loaded on the carrier to obtain the high-entropy alloy core loaded on the carrier.
Optionally, the salt precursor of the high-entropy alloy includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate, and carbonyl salts of a metal element, including at least five of Fe, cu, co, ni, al, mn, cr, V, ti and Sn;
optionally, the second solvent comprises water.
Optionally, the step of vapor phase reducing the high-entropy alloy core precursor supported on the carrier to produce the high-entropy alloy core supported on the carrier comprises:
and (3) reducing the high-entropy alloy core precursor loaded on the carrier for 0.5-3 h at 800-1500 ℃ in a mixed atmosphere of nitrogen and hydrogen.
In the above examples, the high-entropy alloy core is produced by gas phase reduction, and high-temperature calcination ensures the formation of an alloy homogeneous phase of the high-entropy alloy core.
In a third aspect, the present application example provides a fuel cell including the oxygen reduction catalyst of the above-described embodiment.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a cross-sectional view of an active particle of an embodiment of the present application;
FIG. 2 is a cyclic voltammogram of the oxygen reduction catalysts of example 1, comparative examples 1-2 of the present application;
FIG. 3 is a durability test chart of the oxygen reduction catalyst of example 1 of the present application;
FIG. 4 is a durability test chart of the oxygen reduction catalyst of comparative example 1 of the present application;
FIG. 5 is a cyclic voltammogram of the oxygen reduction catalyst of example 1 and examples 3 to 4 of the present application.
Icon: 10-active particles; 100-high entropy alloy nuclei; 200-transition metal sub-shells; 300-platinum rich sheath.
Detailed Description
Proton exchange membrane fuel cells are one of the most promising energy sources for electric vehicles, and oxygen reduction (ORR) is an important cathode reaction in proton exchange membrane fuel cells (Proton exchange membrane fuel by the battery, PEMFC), but the kinetics of oxygen reduction is slower. Pt/C catalysts are considered to be the most effective oxygen reduction catalysts, but Pt/C catalysts are high in cost, low in reserves and poor in stability, and there is still a need for improvement in mass production when fuel cell automobiles are used.
At present, research on non-noble metal catalysts is focused on transition metal catalysts, which are low in cost and abundant in resources, but the dissolution of transition metals in an acidic environment can lead to poor stability. Low platinum catalysts are currently the most viable development for fuel cells.
The high-entropy alloy is a novel alloy material with a multi-principal element solid solution structure, and the unique properties of high-entropy configuration, atomic chemical disorder, lattice distortion and the like endow the alloy material with the potential of being used as a good electrocatalyst.
Based on the above, the applicant has conducted intensive studies to design an oxygen reduction catalyst in order to reduce the amount of noble metal used in the oxygen reduction catalyst and to improve the stability of the oxygen reduction catalyst.
Referring to fig. 1, the present application provides an oxygen reduction catalyst having a core-shell structure, which includes a support and active particles 10 supported on the support, the active particles 10 having a core-shell structure, the active particles 10 comprising: a high-entropy alloy core 100, a transition metal sub-shell 200, and a platinum-rich shell 300, wherein the transition metal sub-shell 200 is coated on the high-entropy alloy core 100, and the platinum-rich shell 300 is coated on the transition metal sub-shell 200.
The mass ratio of the high-entropy alloy core 100 to the carrier is 0.2-0.5:1.
As an example, the mass ratio of the high-entropy alloy core 100 to the carrier may be 0.2:1, 0.3:1, 0.4:1, or 0.5:1.
Optionally, the high-entropy alloy core 100 includes the following metallic elements: fe. Cu, co, ni, al, mn, cr, V, ti and Sn.
As an example, the high-entropy alloy core 100 may include the following metallic elements: fe. Cu, co, ni and Mn.
Alternatively, in the high-entropy alloy core, the atomic number of each metal element accounts for 5% -30% of the total atomic number of the high-entropy alloy.
As an example, in the high-entropy alloy core, the percentage of the atomic number of each metal element to the total atomic number of the high-entropy alloy may be 5%, 8%, 10%, 15%, 20%, 25% or 30%.
And it should be noted that, in the high-entropy alloy core, the percentage of the atomic number of each metal element to the total atomic number of the high-entropy alloy may be the same or different. For example, in the FeCuCoNiMn high-entropy alloy core, the atomic number of each of the five metal elements Fe, cu, co, ni and Mn is 20% of the total atomic number of the high-entropy alloy; or in FeCuCoNiMn high-entropy alloy core, the atomic number of Fe is 30 percent of the total atomic number of the high-entropy alloy, the atomic number of Cu is 30 percent of the total atomic number of the high-entropy alloy, the atomic number of Co is 30 percent of the total atomic number of the high-entropy alloy, the atomic number of Ni is 5 percent of the total atomic number of the high-entropy alloy, and the atomic number of Mn is 5 percent of the total atomic number of the high-entropy alloy.
Alternatively, the support is a carbon support.
The carbon carrier can relieve the agglomeration of alloy nano particles in the high-temperature ordering process and enhance the conductivity in the catalyst reaction process.
Optionally, the carbon support comprises mesoporous carbon, hollow carbon spheres, carbon nanotubes, carbon black, graphitic carbon or graphene.
The transition metal sub-shell 200 includes M metal including any one or more of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
The platinum-rich housing 300 includes platinum metal and G metal, and the mass of the G metal is 1% to 5% of the mass of the platinum metal.
When the mass of the G metal is 1% -5% of the mass of the platinum metal, a small amount of the G metal can occupy the positions, such as the edges and the vertexes, of the shell, which are easy to dissolve and separate out transition metal in the reaction process, preferentially when the core-shell structure is formed by heat treatment of the catalyst, so that the leaching path of the transition metal in the sub-shell is blocked, and the platinum metal still maintains higher activity in the platinum-rich shell 300, thereby ensuring that the catalyst has higher catalytic activity for oxygen reduction reaction.
As an example, the mass of the G metal may be 1%, 2%, 3%, 4% or 5% of the mass of the platinum metal.
The G metal includes any one or more of Mo, au, W, hf and Ta.
The mass ratio of the high-entropy alloy core to the platinum-rich shell 300 is 1:1-5, and the mass ratio of the transition metal sub-shell 200 to the platinum-rich shell 300 is 1:1-5.
As an example, the mass ratio of the high-entropy alloy core and the platinum-rich shell 300 may be 1:1, 1:2, 1:3, 1:4, or 1:5, and the mass ratio of the transition metal sub-shell 200 and the platinum-rich shell 300 may be 1:1, 1:2, 1:3, 1:4, or 1:5.
The high-entropy alloy core is positioned in the core-shell structure, has small influence on the oxygen reduction catalytic activity of the catalyst, and can ensure that strong alloy bonds are formed between internal alloys through strong interaction. The G metal can form strong G-M and G-Pt bonds with the transition metal sub-shell 200 and the platinum-rich outer shell 300 respectively, so that the outward precipitation of transition metal in the sub-shell in the reaction process is inhibited, the chemical adsorption of oxygen element in the reaction process is enhanced, and the adsorption of Pt to O is reduced. The oxygen reduction catalyst reduces the use amount of platinum, and platinum atoms are enriched on the outer surface layer of the structure, so that the utilization efficiency of the platinum atoms of the catalyst is improved on the premise of low platinum loading rate, the catalyst is ensured to have higher catalytic activity of oxygen reduction reaction, and the stability of the catalyst is improved.
The application also provides a preparation method of the oxygen reduction catalyst of the embodiment, which comprises the following steps:
s1, preparing a high-entropy alloy core loaded on a carrier
Mixing a carrier, a salt precursor of the high-entropy alloy and a second solvent, performing ball milling and dispersing to obtain a precursor of the high-entropy alloy core loaded on the carrier, performing vacuum freeze drying treatment on the precursor of the high-entropy alloy core loaded on the carrier to obtain precursor powder of the high-entropy alloy core loaded on the carrier, and performing gas phase reduction on the precursor powder of the high-entropy alloy core loaded on the carrier to obtain the high-entropy alloy core loaded on the carrier.
Optionally, the mass ratio of the salt precursor of the high-entropy alloy and the second solvent is 1:5-20.
Optionally, the salt precursor of the high entropy alloy includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salts of a metal element, including at least five of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
Optionally, the second solvent comprises water.
Optionally, the ball milling time is 2-5 h.
Optionally, the ball milling rotating speed is 300 r/min-1000 r/min.
The vacuum freeze-drying treatment can sublimate the second solvent in the high-entropy alloy core precursor loaded on the carrier, so as to obtain the high-entropy alloy core precursor powder loaded on the carrier. The vacuum freeze-drying treatment comprises the steps of mixing the mixed and dispersed high-entropy alloy core precursor loaded on the carrier with a proper amount of liquid nitrogen, quick-freezing for 10-20 min, transferring to a freezing refrigerator at-30-150 ℃ for pre-freezing for 3-8 h, transferring to a freeze dryer for vacuum freeze-drying treatment, heating from-30-150 ℃ to 60-90 ℃ with the vacuum degree of 20 Pa-50 Pa, and then continuously preserving heat for 15-25 h to obtain the high-entropy alloy core precursor powder loaded on the carrier.
The step of preparing the oxygen reduction catalyst by gas phase reduction of the high-entropy alloy core precursor powder loaded on the carrier comprises the following steps:
placing high-entropy alloy nuclear precursor powder loaded on a carrier into a reaction container, then introducing nitrogen into the reaction container to discharge air in the reaction container, then introducing hydrogen into the reaction container, heating the reaction container to 800-1500 ℃, preserving heat for 0.5-3 h, closing introducing hydrogen, and keeping introducing nitrogen until the reaction container is cooled to room temperature.
Optionally, the heating rate is 2 ℃/min to 20 ℃/min.
Optionally, the nitrogen gas is introduced at a rate of 100mL/min to 700mL/min.
Optionally, in the heat preservation process, the volume ratio of the nitrogen to the hydrogen is 5:1-50:1.
S2, preparing oxygen reduction catalyst
And performing ball milling and dispersing on the salt precursor of the transition metal, the salt precursor of the G metal, the platinum salt precursor, the first solvent and the prepared high-entropy alloy core loaded on the carrier to prepare an oxygen reduction catalyst precursor, performing vacuum freeze drying treatment on the oxygen reduction catalyst precursor to obtain oxygen reduction catalyst precursor powder, and performing gas phase reduction on the oxygen reduction catalyst precursor powder to prepare the oxygen reduction catalyst.
Optionally, the mass ratio of the mass sum of the transition metal salt precursor, the G metal salt precursor, the platinum salt precursor and the high-entropy alloy core to the first solvent is 1:5-20.
Optionally, the salt precursor of the transition metal comprises any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salts of the M metal, which comprises any one or more of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
Optionally, the salt precursor of metal G includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate, and carbonyl salts of metal G.
Optionally, the platinum salt precursor comprises chloroplatinic acid salt and/or platinum acetylacetonate.
Optionally, the first solvent comprises water.
Optionally, the ball milling time is 2-5 h.
Optionally, the ball milling rotating speed is 300 r/min-1000 r/min.
The vacuum freeze-drying process can sublimate the first solvent in the oxygen reduction catalyst precursor to obtain oxygen reduction catalyst precursor powder. The vacuum freeze drying treatment comprises the steps of firstly mixing the oxygen reduction catalyst precursor after mixing and dispersing with a proper amount of liquid nitrogen, quick freezing for 10-20 min, transferring to a freezing refrigerator at-30-150 ℃ for pre-freezing for 3-8 h, transferring to a freeze dryer for vacuum freeze drying treatment, heating from-30-150 ℃ to 60-90 ℃ and keeping the vacuum degree at 20 Pa-50 Pa for 15-25 h, and obtaining the oxygen reduction catalyst precursor powder.
The step of preparing the oxygen reduction catalyst by gas phase reduction of the oxygen reduction catalyst precursor powder comprises the following steps:
placing oxygen reduction catalyst precursor powder into a reaction container, then introducing nitrogen into the reaction container to discharge air in the reaction container, then introducing hydrogen into the reaction container, heating the reaction container to 500-900 ℃, preserving heat for 0.5-3 h, closing introducing hydrogen, and keeping introducing nitrogen to cool to room temperature.
Optionally, the heating rate is 2 ℃/min to 20 ℃/min.
Optionally, the nitrogen gas is introduced at a rate of 100mL/min to 700mL/min.
Optionally, in the heat preservation process, the volume ratio of the nitrogen to the hydrogen is 5:1-50:1.
The preparation method of the oxygen reduction catalyst can simultaneously construct the transition metal sub-shell and the platinum-rich shell through gas phase reduction, and the G metal can promote the formation of the transition metal sub-shell and the platinum-rich shell.
Embodiments of the present application will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustration of the present application and should not be construed as limiting the scope of the present application. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
An oxygen reduction catalyst, a method of preparing the same, and a fuel cell according to the present application are described in further detail below with reference to examples.
Example 1
The embodiment of the application provides an oxygen reduction catalyst and a preparation method thereof, wherein the method comprises the following steps:
s1, preparing a high-entropy alloy core loaded on a carrier
S11, weighing 0.285g FeCl 2 ·4H 2 O、0.314g CuSO 4 ·5H 2 O、0.395gCo(NO 3 ) 2 ·6H 2 O、0.395g Ni(NO 3 ) 2 ·6H 2 O、0.369g C 10 H 14 MnO 4 Dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S12, taking a 50mL ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of carbon black XC-72, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the high-entropy alloy core precursor loaded on the carrier.
S13, transferring the high-entropy alloy core precursor loaded on the carrier into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S14, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then continuously preserving heat for 20 hours to obtain the high-entropy alloy core precursor powder loaded on the carrier.
S15, transferring the high-entropy alloy core precursor powder loaded on the carrier into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating from 20 ℃ to 900 ℃ at a heating rate of 5 ℃/min, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the room temperature to obtain the high-entropy alloy core loaded on the carrier.
S2, preparing oxygen reduction catalyst
S21, weighing 0.806g of platinum acetylacetonate, 1.975g of Co (NO) 3 ) 2 ·6H 2 O and 0.086g of sodium molybdate are dissolved in 20g of ultrapure water, and the precursor solution is obtained after ultrasonic dispersion for 20 min.
S22, taking a 50ml ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of the prepared high-entropy alloy core loaded on the carrier, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the oxygen reduction catalyst precursor.
S23, transferring the oxygen reduction catalyst precursor into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S24, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then keeping the temperature for 20 hours to obtain the oxygen reduction catalyst precursor powder.
S25, transferring the oxygen reduction catalyst precursor powder into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating up at a heating rate of 5 ℃/min, heating up to 900 ℃ from 20 ℃, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the temperature to room temperature to prepare the oxygen reduction catalyst.
S26, stirring the prepared oxygen reduction catalyst in a 0.5M nitric acid solution for 0.5h, washing with deionized water to be neutral, and then drying in vacuum to obtain an oxygen reduction catalyst sample.
Example 2
The embodiment of the application provides an oxygen reduction catalyst and a preparation method thereof, wherein the method comprises the following steps:
s1, preparing a high-entropy alloy core loaded on a carrier
S11, 0.285g of Fe is weighedCl 2 ·4H 2 O、0.314g CuSO 4 ·5H 2 O、0.395gCo(NO 3 ) 2 ·6H 2 O、0.395g Ni(NO 3 ) 2 ·6H 2 O、0.317gZn(NO 3 ) 2 ·6H 2 O was dissolved in 20g of ultrapure water, and ultrasonically dispersed for 20min to obtain a precursor solution.
S12, taking a 50mL ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of carbon black XC-72, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the high-entropy alloy core precursor loaded on the carrier.
S13, transferring the high-entropy alloy core precursor loaded on the carrier into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S14, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then continuously preserving heat for 20 hours to obtain the high-entropy alloy core precursor powder loaded on the carrier.
S15, transferring the high-entropy alloy core precursor powder loaded on the carrier into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating from 20 ℃ to 900 ℃ at a heating rate of 5 ℃/min, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the room temperature to obtain the high-entropy alloy core loaded on the carrier.
S2, preparing oxygen reduction catalyst
S21, weighing 0.806g of platinum acetylacetonate, 1.975g of Ni (NO) 3 ) 2 ·6H 2 O、0.147gW(CO) 6 Dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S22, taking a 50ml ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of the prepared high-entropy alloy core loaded on the carrier, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the oxygen reduction catalyst precursor.
S23, transferring the oxygen reduction catalyst precursor into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S24, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then keeping the temperature for 20 hours to obtain the oxygen reduction catalyst precursor powder.
S25, transferring the oxygen reduction catalyst precursor powder into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating up at a heating rate of 5 ℃/min, heating up to 900 ℃ from 20 ℃, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the temperature to room temperature to prepare the oxygen reduction catalyst.
S26, stirring the prepared oxygen reduction catalyst in a 0.5M nitric acid solution for 0.5h, washing with deionized water to be neutral, and then drying in vacuum to obtain an oxygen reduction catalyst sample.
Example 3
The embodiment of the application provides an oxygen reduction catalyst and a preparation method thereof, wherein the method comprises the following steps:
s1, preparing a high-entropy alloy core loaded on a carrier
S11, weighing 0.285g FeCl 2 ·4H 2 O、0.314g CuSO 4 ·5H 2 O、0.395gCo(NO 3 ) 2 ·6H 2 O、0.395g Ni(NO 3 ) 2 ·6H 2 O、0.369g C 10 H 14 MnO 4 Dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S12, taking a 50mL ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of carbon black XC-72, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the high-entropy alloy core precursor loaded on the carrier.
S13, transferring the high-entropy alloy core precursor loaded on the carrier into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S14, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then continuously preserving heat for 20 hours to obtain the high-entropy alloy core precursor powder loaded on the carrier.
S15, transferring the high-entropy alloy core precursor powder loaded on the carrier into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating from 20 ℃ to 900 ℃ at a heating rate of 5 ℃/min, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the room temperature to obtain the high-entropy alloy core loaded on the carrier.
S2, preparing oxygen reduction catalyst
S21, weighing 0.806g of platinum acetylacetonate, 1.975g of Co (NO) 3 ) 2 ·6H 2 O and 0.069g of sodium molybdate are dissolved in 20g of ultrapure water, and the precursor solution is obtained after ultrasonic dispersion for 20 min.
S22, taking a 50ml ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of the prepared high-entropy alloy core loaded on the carrier, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the oxygen reduction catalyst precursor.
S23, transferring the oxygen reduction catalyst precursor into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S24, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then keeping the temperature for 20 hours to obtain the oxygen reduction catalyst precursor powder.
S25, transferring the oxygen reduction catalyst precursor powder into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating up at a heating rate of 5 ℃/min, heating up to 900 ℃ from 20 ℃, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the temperature to room temperature to prepare the oxygen reduction catalyst.
S26, stirring the prepared oxygen reduction catalyst in a 0.5M nitric acid solution for 0.5h, washing with deionized water to be neutral, and then drying in vacuum to obtain an oxygen reduction catalyst sample.
Example 4
The embodiment of the application provides an oxygen reduction catalyst and a preparation method thereof, wherein the method comprises the following steps:
s1, preparing a high-entropy alloy core loaded on a carrier
S11, weighing 0.285g FeCl 2 ·4H 2 O、0.314g CuSO 4 ·5H 2 O、0.395gCo(NO 3 ) 2 ·6H 2 O、0.395g Ni(NO 3 ) 2 ·6H 2 O、0.369g C 10 H 14 MnO 4 Dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S12, taking a 50mL ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of carbon black XC-72, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the high-entropy alloy core precursor loaded on the carrier.
S13, transferring the high-entropy alloy core precursor loaded on the carrier into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S14, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then continuously preserving heat for 20 hours to obtain the high-entropy alloy core precursor powder loaded on the carrier.
S15, transferring the high-entropy alloy core precursor powder loaded on the carrier into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating from 20 ℃ to 900 ℃ at a heating rate of 5 ℃/min, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the room temperature to obtain the high-entropy alloy core loaded on the carrier.
S2, preparing oxygen reduction catalyst
S21、0.806g of platinum acetylacetonate, 1.975g of Co (NO) were weighed out 3 ) 2 ·6H 2 O and 0.473g of sodium molybdate are dissolved in 20g of ultrapure water, and the precursor solution is obtained by ultrasonic dispersion for 20 min.
S22, taking a 50ml ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of the prepared high-entropy alloy core loaded on the carrier, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the oxygen reduction catalyst precursor.
S23, transferring the oxygen reduction catalyst precursor into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S24, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then keeping the temperature for 20 hours to obtain the oxygen reduction catalyst precursor powder.
S25, transferring the oxygen reduction catalyst precursor powder into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating up at a heating rate of 5 ℃/min, heating up to 900 ℃ from 20 ℃, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the temperature to room temperature to prepare the oxygen reduction catalyst.
S26, stirring the prepared oxygen reduction catalyst in a 0.5M nitric acid solution for 0.5h, washing with deionized water to be neutral, and then drying in vacuum to obtain an oxygen reduction catalyst sample.
Comparative example 1
The comparative example of the present application provides an oxygen reduction catalyst.
JM40% platinum carbon catalyst:
brand: johnson Matthey;
model: hispec 4000;
platinum content: 40%.
Comparative example 2
The comparative example of the present application provides an oxygen reduction catalyst and a method for preparing the same, which comprises the steps of:
s1, preparing a high-entropy alloy core loaded on a carrier
S11, weighing 0.285g FeCl 2 ·4H 2 O、0.314g CuSO 4 ·5H 2 O、0.395gCo(NO 3 ) 2 ·6H 2 O、0.395g Ni(NO 3 ) 2 ·6H 2 O、0.369g C 10 H 14 MnO 4 Dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S12, taking a 50mL ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of carbon black XC-72, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the high-entropy alloy core precursor loaded on the carrier.
S13, transferring the high-entropy alloy core precursor loaded on the carrier into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S14, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then continuously preserving heat for 20 hours to obtain the high-entropy alloy core precursor powder loaded on the carrier.
S15, transferring the high-entropy alloy core precursor powder loaded on the carrier into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating from 20 ℃ to 900 ℃ at a heating rate of 5 ℃/min, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the room temperature to obtain the high-entropy alloy core loaded on the carrier.
S2, preparing oxygen reduction catalyst
S21, weighing 0.806g of platinum acetylacetonate, dissolving in 20g of ultrapure water, and performing ultrasonic dispersion for 20min to obtain a precursor solution.
S22, taking a 50ml ball milling tank, placing the precursor solution into the ball milling tank, weighing 2g of the prepared high-entropy alloy core loaded on the carrier, pouring into the ball milling tank, and ball milling and soaking for 3 hours at a ball milling rotating speed of 500r/min to obtain the oxygen reduction catalyst precursor.
S23, transferring the oxygen reduction catalyst precursor into a glass culture dish, pouring a proper amount of liquid nitrogen, quick-freezing for 15min, and pre-freezing for 5h in a freezing refrigerator at the temperature of minus 40 ℃.
S24, placing the culture dish into a freeze dryer for vacuum freeze drying treatment, heating the temperature from-40 ℃ to 80 ℃, keeping the vacuum degree at 30Pa, and then keeping the temperature for 20 hours to obtain the oxygen reduction catalyst precursor powder.
S25, transferring the oxygen reduction catalyst precursor powder into a tube furnace, continuously introducing 500mL/min nitrogen into the tube furnace for 15min to discharge gaps in the tube furnace, and continuously introducing 20mL/min hydrogen. The heating program of the tube furnace is as follows: heating up at a heating rate of 5 ℃/min, heating up to 900 ℃ from 20 ℃, preserving heat for 3 hours at 900 ℃, stopping introducing hydrogen after the reaction is finished, continuously introducing nitrogen to the temperature, and recovering the temperature to room temperature to prepare the oxygen reduction catalyst.
S26, stirring the prepared oxygen reduction catalyst in a 0.5M nitric acid solution for 0.5h, washing with deionized water to be neutral, and then drying in vacuum to obtain an oxygen reduction catalyst sample.
Test example 1
The oxygen reduction catalyst samples prepared in examples 1 to 4 and comparative examples 1 to 2 were respectively subjected to electrochemical tests, and the results are shown in fig. 2 to 4.
10mg of the oxygen reduction catalysts prepared in examples 1-4 and comparative examples 1-2 were accurately weighed into a glass bottle, and 10mL of Nafion solution was added for ultrasonic dispersion to prepare an oxygen reduction catalyst slurry sample, wherein the concentration of the oxygen reduction catalyst in the oxygen reduction catalyst slurry sample was 1mg/mL. Taking 10 mu L of oxygen reduction catalyst slurry sample by a liquid-transferring gun, uniformly dripping the oxygen reduction catalyst slurry sample on the surface of a smooth and clean glassy carbon electrode in a separated mode, mounting the electrode on a rotary table, and carrying out N-phase reaction on the electrode 2 Blow drying to be used as a working electrode. At 0.5M H 2 SO 4 N is led into the electrolytic cell 2 And (5) deoxidizing.
CV test: the electrodes are placed in an electrolytic cell to form a three-electrode system. Wherein the reference electrode is Hg/Hg 2 SO 4 The counter electrode is a platinum net electrode, and the electrolyte is N 2 Saturated H at 25℃constant temperature of 0.5M 2 SO 4 The CV test window is set to be swept at 50mV/s, -0.632-0.328VAfter 20 cycles (10 circles) are performed to fully activate the catalyst and the hydrogen desorption peak is basically stable, the electrochemical active area ECSA of the catalyst is calculated according to the data of the last circle.
As shown in FIG. 2, FIG. 2 is a cyclic voltammogram of the oxygen reduction catalyst of example 1 and comparative examples 1 to 2, the electrochemical active area of the oxygen reduction catalyst of comparative example 1 being 53.74m 2 gPt the electrochemically active area of the oxygen reduction catalyst of example 1 was 58.23m 2 Per gPt, the electrochemically active area of the oxygen reduction catalyst of comparative example 2 was 31.50m 2 /gPt. It can be seen that the electrochemical active area of the oxygen reduction catalyst of example 1 is greater than that of the oxygen reduction catalyst of comparative example 1 and that of the oxygen reduction catalyst of comparative example 2, i.e., example 1 is superior to that of comparative example 1 and comparative example 2.
As shown in FIGS. 3 to 4, FIG. 3 is a durability test of the oxygen reduction catalyst of example 1, and the electrochemical active area ECSA after scanning for 20000 turns at a scanning speed of 50mV/s, -0.632 to 0.328V was measured by 58.23m 2 /gPt down to 52.31m 2 /gPt, 10.17% drop. FIG. 4 is a durability test of the oxygen reduction catalyst of comparative example 1, the electrochemically active area ECSA was measured as 53.74m after scanning for only 5000 cycles at a scanning speed of 50mV/s, -0.632 to 0.328V 2 /gPt down to 33.86m 2 /gPt, 36.99% drop. That is, the stability of the oxygen reduction catalyst of example 1 was better than that of the oxygen reduction catalyst of comparative example 1.
As shown in fig. 5, fig. 5 is a cyclic voltammogram of the oxygen reduction catalyst of example 1 and examples 3 to 4, wherein the mass of Mo in the oxygen reduction catalyst of example 1 is 1% of the mass of Pt, the mass of Mo in the oxygen reduction catalyst of example 3 is 0.8% of the mass of Pt, and the mass of Mo in the oxygen reduction catalyst of example 4 is 5.5% of the mass of Pt. The electrochemically active area of the oxygen reduction catalyst of example 1 was 58.23m 2 gPt the electrochemically active area of the oxygen reduction catalyst of example 3 was 47.83m 2 Per gPt, the electrochemically active area of the oxygen reduction catalyst of example 4 was 42.14m 2 /gPt. It can be seen that the electrochemical of the oxygen reduction catalyst of example 1The area of the chemical activity was larger than that of the oxygen reduction catalyst of example 3 and that of the oxygen reduction catalyst of example 4, i.e., example 1 was superior to that of the oxygen reduction catalysts of example 3 and example 4.
The foregoing is merely a specific embodiment of the present application and is not intended to limit the present application, and various modifications and variations may be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (18)
1. A method for preparing an oxygen reduction catalyst, comprising: providing a high-entropy alloy core loaded on a carrier, mixing and dispersing a salt precursor of transition metal, a salt precursor of G metal, a platinum salt precursor, the high-entropy alloy core loaded on the carrier and a first solvent to prepare an oxygen reduction catalyst precursor, and then carrying out gas phase reduction on the oxygen reduction catalyst precursor to prepare the oxygen reduction catalyst;
the oxygen reduction catalyst includes the carrier and active particles supported on the carrier, the active particles having a core-shell structure, the active particles including: the high-entropy alloy core, a transition metal sub-shell coated on the high-entropy alloy core, and a platinum-rich shell coated on the transition metal sub-shell, wherein the platinum-rich shell comprises platinum metal and G metal, and the G metal comprises any one or more of Mo, au, W, hf and Ta.
2. The method for producing an oxygen reduction catalyst according to claim 1, wherein the mass of the G metal in the platinum-rich shell is 1 to 5% of the mass of the platinum metal.
3. The method for producing an oxygen reduction catalyst according to claim 1, wherein a mass ratio of the high-entropy alloy core to the carrier is 0.2 to 0.5:1.
4. The method for producing an oxygen reduction catalyst according to claim 1, wherein the carrier is a carbon carrier.
5. The method for producing an oxygen reduction catalyst according to claim 4, wherein the carbon support comprises mesoporous carbon, hollow carbon spheres, carbon nanotubes, carbon black, graphitic carbon or graphene.
6. The method for producing an oxygen reduction catalyst according to claim 1, wherein the atomic number of each metal element in the high-entropy alloy core is 5% to 30% of the total atomic number of the high-entropy alloy.
7. The method for producing an oxygen-reducing catalyst according to claim 1, wherein the mass ratio of the high-entropy alloy core to the platinum-rich shell is 1:1 to 5, and the mass ratio of the transition metal sub-shell to the platinum-rich shell is 1:1 to 5.
8. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, wherein the salt precursor of the transition metal includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salt of M metal including any one or more of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
9. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, wherein the salt precursor of G metal includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salts of G metal.
10. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, wherein the platinum salt precursor comprises chloroplatinic acid salt and/or platinum acetylacetonate.
11. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, wherein the first solvent comprises water.
12. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, characterized in that the step of subjecting the oxygen reduction catalyst precursor to gas phase reduction to produce the oxygen reduction catalyst comprises:
and reducing the oxygen reduction catalyst precursor for 0.5 to 3 hours at the temperature of between 500 and 900 ℃ in a mixed atmosphere of nitrogen and hydrogen.
13. The method for preparing an oxygen reduction catalyst according to claim 12, wherein the volume ratio of nitrogen to hydrogen in the mixed atmosphere is 5:1 to 50:1.
14. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, characterized in that the oxygen reduction catalyst precursor is subjected to vacuum freeze-drying treatment to obtain an oxygen reduction catalyst precursor powder before the oxygen reduction catalyst precursor is subjected to gas-phase reduction.
15. The method for producing an oxygen reduction catalyst according to any one of claims 1 to 7, wherein the high-entropy alloy core supported on the carrier is produced by:
and mixing and dispersing the carrier, the salt precursor of the high-entropy alloy and the second solvent to obtain a high-entropy alloy core precursor loaded on the carrier, and carrying out gas-phase reduction on the high-entropy alloy core precursor loaded on the carrier to obtain the high-entropy alloy core loaded on the carrier.
16. The method for producing an oxygen reduction catalyst according to claim 15, wherein the salt precursor of the high-entropy alloy includes any one or more of nitrate, halide, acetylacetonate, sulfate, cyanide, acetate and carbonyl salts of a metal element including at least five of Fe, cu, co, ni, al, mn, cr, V, ti and Sn.
17. The method for producing an oxygen reduction catalyst according to claim 15, wherein the second solvent comprises water.
18. The method for producing an oxygen reduction catalyst according to claim 15, characterized in that the step of subjecting the high-entropy alloy core precursor supported on the carrier to vapor phase reduction to produce the high-entropy alloy core supported on the carrier comprises:
and (3) reducing the high-entropy alloy core precursor loaded on the carrier for 0.5-3 h at 800-1500 ℃ in a mixed atmosphere of nitrogen and hydrogen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN115172783A (en) * | 2022-06-09 | 2022-10-11 | 中山大学 | Carbon-base-free loaded high-entropy alloy particle and preparation method and application thereof |
| CN115188978A (en) * | 2022-08-05 | 2022-10-14 | 中国科学技术大学 | Preparation method and application of supported polycrystalline surface defect high-entropy alloy catalyst |
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| CN115172783A (en) * | 2022-06-09 | 2022-10-11 | 中山大学 | Carbon-base-free loaded high-entropy alloy particle and preparation method and application thereof |
| CN115188978A (en) * | 2022-08-05 | 2022-10-14 | 中国科学技术大学 | Preparation method and application of supported polycrystalline surface defect high-entropy alloy catalyst |
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| Title |
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| "High-entropy alloy stabilized and activated Pt clusters for highly efficient electrocatalysis";Wenhui Shi等;《SusMat》;第第2卷卷(第第2期期);第186-196页 * |
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