A supported single-atom alloy catalyst, a preparation method thereof, and applications thereof

Abstract

The present invention discloses a supported single-atom alloy catalyst, a preparation method thereof and an application thereof, belonging to the technical field of heterogeneous catalysis. The supported single-atom alloy catalyst comprises a support, intermetallic compound nanoparticles loaded on the support, and single-atom metals dispersed on the surface of the intermetallic compound nanoparticles; the reduction potential of the single-atom metals is between those of the two metals in the intermetallic compound; the single-atom metals are atomically dispersed by displacing one of the metals on the surface of the intermetallic compound nanoparticles. The supported single-atom alloy catalyst prepared by the present invention exhibits extremely high selectivity and activity for the direct pathway of formic acid oxidation reaction as an anode catalyst for direct formic acid fuel cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of heterogeneous catalysis, and more specifically, relates to a supported single-atom alloy catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Direct formic acid fuel cells have a relatively high theoretical voltage, energy density, and low polymer membrane permeability. The anodic formic acid oxidation reaction uses liquid formic acid as a fuel, and 2 electrons are released during the oxidation process to produce carbon dioxide. However, during the catalytic oxidation of formic acid by a single metal such as platinum, it is easily occupied by adsorbed carbon monoxide intermediates and removed at an extremely high overpotential, resulting in the poisoning of active sites. Therefore, it is of great significance to avoid the formation of adsorbed carbon monoxide intermediates and promote the direct oxidation of formic acid to carbon dioxide at a lower potential. To solve the problem of poisoning of single-metal platinum by adsorbed carbon monoxide intermediates, by suppressing continuous platinum atomic sites and isolating them, the binding strength to carbon monoxide intermediates can be weakened, thereby improving the anti-poisoning performance and thus enhancing the activity of catalytic formic acid electrooxidation at low potentials. Therefore, it is necessary to adjust the dispersion degree of platinum to make it dispersed at the atomic level. However, the current methods mainly achieve this by reducing the proportion of platinum in the alloy, with many influencing factors and it is difficult to accurately control the dispersion degree of platinum. Summary of the Invention

[0003] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a supported single-atom alloy catalyst, a preparation method thereof, and an application thereof, aiming to self-limitingly grow single atoms and precisely regulate the coordination environment of active atoms, thereby solving the technical problems of reducing a large number of proportion optimization experiments and the variety of coordination environments.

[0004] To achieve the above object, according to one aspect of the present invention, a supported single-atom alloy catalyst is provided, comprising a carrier, intermetallic compound nanoparticles supported on the carrier, and single-atom metals dispersed on the surface of the intermetallic compound nanoparticles; the reduction potential of the single-atom metal is between the two metals in the intermetallic compound; the single-atom metal forms an ordered dispersion by displacing one of the metals on the surface of the intermetallic compound nanoparticles.

[0005] Preferably, the single-atom metal is a platinum group metal, and the two metals in the intermetallic compound are gold and a non-noble metal respectively; preferably, the non-noble metal is copper or zinc, and preferably, the platinum group metal is platinum or palladium.

[0006] Preferably, the mass fraction of the noble metal element in the supported single-atom alloy catalyst is 20-60%.

[0007] According to another aspect of the present invention, a preparation method of a supported single-atom alloy catalyst is provided, comprising the following steps:

[0008] (1) Dissolve a gold salt and a non-noble metal salt in a solvent to obtain a salt solution, and disperse a support in the salt solution. The gold salt and the non-noble metal salt are adsorbed on the support, and after stirring under heating conditions to evaporate the solvent to dryness, a solid powder is obtained.

[0009] (2) Heat the solid powder once under a reducing atmosphere for reduction to obtain bimetallic nanoparticles supported on the support; subject the bimetallic nanoparticles supported on the support to secondary heat treatment under a reducing atmosphere to order the bimetallic nanoparticles and form intermetallic compound nanoparticles.

[0010] (3) Disperse the intermetallic compound nanoparticles supported on the support in a solvent, add a third metal salt with a reduction potential between the two metals in the intermetallic compound for a displacement reaction, and then perform centrifugal separation and drying to obtain the supported single-atom alloy catalyst.

[0011] According to another aspect of the present invention, there is provided a method for preparing a supported single-atom alloy catalyst, comprising the following steps:

[0012] (1) Dissolve a gold salt and a non-noble metal salt in a solvent to obtain a salt solution, and disperse a support in the salt solution. The gold salt and the non-noble metal salt are adsorbed on the support, and after stirring under heating conditions to evaporate the solvent to dryness, a solid powder is obtained.

[0013] (2) Heat the solid powder once under a reducing atmosphere for reduction to obtain bimetallic nanoparticles supported on the support.

[0014] (3) Disperse the bimetallic nanoparticles supported on the support in a solution containing tris(hydroxymethyl)aminomethane and dopamine hydrochloride to obtain a support wrapped with polydopamine, and the support supports bimetallic nanoparticles.

[0015] (4) Subject the bimetallic nanoparticles supported on the support wrapped with polydopamine to secondary heat treatment under a reducing atmosphere to carbonize the polydopamine and order the bimetallic nanoparticles, and obtain a support of non-noble metal single atoms and nitrogen-doped carbon, and the support supports intermetallic compound nanoparticles.

[0016] (5) Disperse the intermetallic compound nanoparticles supported on the support in a solvent, add a third metal salt with a reduction potential between the two metals in the intermetallic compound for a displacement reaction, and then perform centrifugal separation and drying to obtain the supported single-atom alloy catalyst.

[0017] It should be noted that the above-mentioned solvent is a volatile and non-toxic solvent, and can be exemplified by water.

[0018] Preferably, the non-noble metal salt is a copper salt or a zinc salt; the third metal salt is a salt containing a platinum group metal. The atomic ratio of gold to copper in the gold salt and the copper salt is 1:(0.3-3); the atomic ratio of gold to zinc in the gold salt and the zinc salt is 1:(0.8-2); preferably, the atomic ratio of the third metal to gold in the third metal salt and the gold salt is 1:(5-100); preferably, the salt containing a platinum group metal is a platinum salt or a palladium salt.

[0019] Preferably, the heating temperature of the first heating is 150°C to 300°C, and the heating time is 2-5 h; the heating temperature of the second heat treatment is 700°C to 900°C, the heating time is 4-6 h, and the heating rate is 2-10°C / min.

[0020] Preferably, the carrier is at least one of carbon black, Ketjen black, carbon nanotubes, spherical silica, nano-silica, and carbon formed by carbonizing polydopamine.

[0021] Preferably, the carrier is at least one of carbon black, Ketjen black, carbon nanotubes, spherical silica, nano-silica, and carbon formed by carbonizing polydopamine; when the carrier is spherical silica or nano-silica, after the second heat treatment in step (4), the silica is removed by a sodium hydroxide etching method.

[0022] Preferably, the gold salt is at least one of sodium tetrachloroaurate dihydrate, ammonium tetrachloroaurate hydrate, chloroauric acid trihydrate, gold(I) chloride, potassium chloroaurate, and gold(III) chloride hydrate.

[0023] Preferably, the copper salt is at least one of cuprous chloride, anhydrous copper sulfate, copper(II) chloride dihydrate, and anhydrous copper(II) chloride; the zinc salt is at least one of zinc chloride, zinc sulfate, and zinc nitrate. The platinum salt is at least one of chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, potassium chloroplatinate(II), platinum acetylacetonate, platinum dichloride, and platinum tetrachloride; the palladium salt is at least one of palladium chloride, palladium sulfate, palladium acetate, palladium nitrate, sodium tetrachloropalladate, ammonium chloropalladate, and palladium acetylacetonate.

[0024] According to another aspect of the present invention, there is provided an application of a supported single-atom alloy catalyst for electrocatalytic formic acid oxidation reaction.

[0025] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, at least the following beneficial effects can be achieved.

[0026] (1) In the supported single-atom alloy catalyst provided by the present invention, the single-atom metal forms an ordered dispersion by partially replacing one metal on the surface of the intermetallic compound nanoparticles. The dispersion state of the single-atom metal on its surface can be precisely regulated by changing the proportion of the intermetallic compound, greatly weakening the poisoning of the catalyst by carbon monoxide intermediates, which is beneficial to enhancing the activity of electrocatalytic formic acid oxidation. It enables the full utilization of metal atoms as active sites and is conducive to reducing the cost of the catalyst.

[0027] (2) In the preparation method provided by this patent, a double-metal alloy is first formed by heating and reduction once, and the crystal phase of an ordered intermetallic compound is formed by secondary heat treatment, that is, the arrangement of the two metals in the intermetallic compound is in a regular state. When a displacement reaction is carried out between the intermetallic compound and a third metal salt whose reduction potential is between the two metals in the intermetallic compound, one metal with a lower reduction potential on the surface of the intermetallic compound will be replaced by the third metal. Due to the regular arrangement of the two metals in the intermetallic compound, the replaced third metal is also in a state of being regularly dispersed on the surface of the intermetallic compound. Even if the third metal is atomically dispersed on the surface of the binary intermetallic compound, the dispersion state of the third metal can be controlled more precisely, avoiding a large number of reactant ratio optimization experiments in the prior art.

[0028] (3) The present invention can affect the adsorption energy of the surface active metal for reaction species by changing the composition of the binary intermetallic compound, further realizing the optimization of the activity of the electrocatalytic formic acid oxidation reaction.

[0029] (4) In the preparation method provided by the present invention, the carrier can also be a carbon carrier doped with nitrogen and non-precious metal single atoms. Such a carrier has the advantages of affecting the electronic structure of the supported nanoparticles and synergistic catalysis. Description of the Drawings

[0030] Figure 1 X-ray diffraction pattern of platinum (Pt-AuCu / SiO 2 ) atomically dispersed on the surface of silica-supported gold-copper (1:1) intermetallic compound nanoparticles;

[0031] Figure 2 Scanning transmission electron microscopy image with atomic resolution of platinum (Pt-AuCu) atomically dispersed on the surface of gold-copper (1:1) intermetallic compound nanoparticles;

[0032] Figure 3 In (a) is the scanning transmission electron microscopy image of platinum atomically dispersed on the surface of gold-copper (1:1) intermetallic compound nanoparticles in Example 2, Figure 3 In (b)-(d) are the energy-dispersive X-ray spectroscopy maps of platinum atomically dispersed on the surface of gold-copper (1:1) intermetallic compound nanoparticles in Example 2;

[0033] Figure 4 is the X-ray diffraction pattern of platinum (Pt-AuCu 3 / SiO 2 ) atomically dispersed on the surface of silica-supported gold-copper (1:3) intermetallic nanoparticles;

[0034] Figure 5 Among them, (a) is the cyclic voltammetry curve of pure Pt catalyzing formic acid oxidation, Figure 5 and (b) is the linear voltammetry curve of platinum (Pt-AuCu) atomically dispersed on the surface of gold-copper (1:1) intermetallic nanoparticles catalyzing formic acid oxidation. Detailed implementation manners

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] Example 1

[0037] First step: Dissolve chloroauric acid and copper chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to copper to be 3:1, and stir and heat until the water is completely volatilized;

[0038] Second step: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200°C for 2 h, then raise the temperature to 800°C for heat treatment for 6 h and then cool naturally to room temperature;

[0039] Third step: Disperse the sample obtained in the second step in a solution of potassium chloroplatinate, control the atomic ratio of platinum to copper to be 1:5, bubble with nitrogen for 5 min, then seal and stir and heat at 60°C for 4 h, then centrifuge and dry to obtain platinum on Au 3 a single-atom alloy catalyst with atomic dispersion on the surface of Cu intermetallic compounds.

[0040] Example 2

[0041] First step: Dissolve chloroauric acid and copper chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to copper to be 1:1, and stir and heat until the water is completely volatilized;

[0042] Step 2: Grind the solid powder obtained in Step 1 and then reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Subsequently, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0043] Step 3: Disperse the sample obtained in Step 2 in a solution containing chloroplatinic acid, control the atomic ratio of platinum to copper to be 1:10, bubble nitrogen through it for 5 min, then seal it and stir and heat it at 60 °C for reaction for 4 h, followed by centrifugal separation and drying to obtain a single-atom alloy catalyst with platinum atomically dispersed on the surface of the AuCu intermetallic compound.

[0044] Example 3

[0045] Step 1: Dissolve chloroauric acid and copper chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to copper to be 1:3, and stir and heat until the water completely evaporates;

[0046] Step 2: Grind the solid powder obtained in Step 1 and then reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Subsequently, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0047] Step 3: Disperse the sample obtained in Step 2 in a solution containing chloroplatinic acid, control the atomic ratio of platinum to copper to be 1:10, bubble nitrogen through it for 5 min, then seal it and stir and heat it at 60 °C for reaction for 4 h, followed by centrifugal separation and drying to obtain a single-atom alloy catalyst with platinum atomically dispersed on the surface of the AuCu intermetallic compound.

[0048] Example 4

[0049] Step 1: Dissolve chloroauric acid and zinc chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to zinc to be 1:1, and stir and heat until the water completely evaporates;

[0050] Step 2: Grind the solid powder obtained in Step 1 and then reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Subsequently, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0051] Step 3: Disperse the sample obtained in Step 2 in a solution containing chloroplatinic acid, control the atomic ratio of platinum to zinc to be 1:5, bubble nitrogen through it for 5 min, then seal it and stir and heat it at 60 °C for reaction for 4 h, followed by centrifugal separation and drying to obtain a single-atom alloy catalyst with platinum atomically dispersed on the surface of the AuZn intermetallic compound.

[0052] Example 5

[0053] Step 1: Dissolve chloroauric acid and copper chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to copper to be 1:3, and stir and heat until the water completely evaporates;

[0054] Step 2: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h;

[0055] Step 3: Disperse the solid powder obtained in the second step in a tris(hydroxymethyl)aminomethane solution with a mass fraction of 1.2 mg / mL, add dopamine hydrochloride, whose mass is 10% relative to silica, stir at room temperature for 24 h to promote dopamine polymerization, and then centrifuge, separate, and dry;

[0056] Step 4: Grind the solid powder obtained in the first step and heat-treat it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 800 °C for 6 h, then naturally cool to room temperature. After etching in 2.0 M sodium hydroxide solution at 50 °C for 4 h, centrifuge, wash, and dry;

[0057] Step 5: Disperse the sample obtained in the second step in a solution containing chloroplatinic acid, control the atomic ratio of platinum to copper to be 1:5, bubble nitrogen for 5 min, then seal and stir and heat at 60 °C for 4 h, and then centrifuge, separate, and dry to obtain a single-atom alloy catalyst with platinum atomically dispersed on the surface of the AuCu intermetallic compound and doped with copper and nitrogen in carbon.

[0058] Example 6

[0059] Step 1: Dissolve chloroauric acid and copper chloride in water, disperse Ketjen black in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to copper to be 3:1, and stir and heat until the water completely evaporates;

[0060] Step 2: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h, and then heat-treat it at 800 °C for 6 h and naturally cool to room temperature;

[0061] Step 3: Disperse the sample obtained in the second step in a solution of potassium chloroplatinate, control the atomic ratio of platinum to copper to be 1:5, bubble nitrogen for 5 min, then seal and stir and heat at 60 °C for 4 h, and then centrifuge, separate, and dry to obtain a single-atom alloy catalyst with platinum atomically dispersed on the surface of the Au 3 Cu intermetallic compound.

[0062] Example 7

[0063] Step 1: Dissolve chloroauric acid and zinc chloride in water, disperse silica in water, control the mass fraction of gold relative to silica to be 10%, and the atomic ratio of gold to zinc to be 1:1. Stir and heat until the water completely evaporates;

[0064] Step 2: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Then, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0065] Step 3: Disperse the sample obtained in the second step in a palladium chloride solution, control the atomic ratio of palladium to zinc to be 1:5, bubble nitrogen for 5 min, then seal and stir and heat at 60 °C for 4 h, followed by centrifugal separation and drying to obtain a single-atom alloy catalyst with Pd atomically dispersed on the surface of the AuZn intermetallic compound.

[0066] Example 8

[0067] Step 1: Dissolve chloroplatinic acid and zinc chloride in water, disperse silica in water, control the mass fraction of platinum relative to silica to be 10%, and the atomic ratio of platinum to zinc to be 1:1. Stir and heat until the water completely evaporates;

[0068] Step 2: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Then, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0069] Step 3: Disperse the sample obtained in the second step in a palladium chloride solution, control the atomic ratio of palladium to zinc to be 1:5, bubble nitrogen for 5 min, then seal and stir and heat at 60 °C for 4 h, followed by centrifugal separation and drying to obtain a single-atom alloy catalyst with Pd atomically dispersed on the surface of the PtZn intermetallic compound.

[0070] Example 9

[0071] Step 1: Dissolve chloroplatinic acid and copper chloride in water, disperse silica in water, control the mass fraction of platinum relative to silica to be 10%, and the atomic ratio of platinum to copper to be 1:1. Stir and heat until the water completely evaporates;

[0072] Step 2: Grind the solid powder obtained in the first step and reduce it in a hydrogen-argon mixed gas with a hydrogen volume fraction of 10% at 200 °C for 2 h. Then, raise the temperature to 800 °C for heat treatment for 6 h and then naturally cool to room temperature;

[0073] Step 3: Disperse the sample obtained in Step 2 in a palladium chloride solution, control the atomic ratio of palladium to copper to be 1:5, bubble nitrogen for 5 min, then seal and stir and heat at 60 °C for 4 h, followed by centrifugation and drying to obtain a single-atom alloy catalyst with Pd atomically dispersed on the surface of the PtCu intermetallic compound.

[0074] Example 10

[0075] Disperse the catalyst powder in a 0.1% Nafion / isopropanol mixture, control the ratio to be 5 mg of catalyst corresponding to 1 mL of dispersion, and ultrasonicate for 5 - 20 min to uniformly disperse the catalyst powder. Pipette 5 μL of the dispersion and dropwise coat it on a glassy carbon electrode and allow it to dry naturally to form a catalyst layer. Using the glassy carbon electrode coated with the catalyst as the working electrode, a carbon rod and a reversible hydrogen electrode as the counter electrode and reference electrode respectively, test the cyclic voltammogram of formic acid oxidation in a nitrogen-saturated 0.5 mol / L sulfuric acid solution containing 0.5 mol / L formic acid at a scan rate of 0.05 V s -1 to test the cyclic voltammogram of catalytic formic acid oxidation.

[0076] Figure 1 is the X-ray diffraction (XRD) pattern of platinum (Pt-AuCu / SiO 2 ) atomically dispersed on the surface of the silica-supported gold-copper (1:1) intermetallic compound nanoparticles in Example 2. By comparing with the standard gold-copper (1:1) intermetallic compound and silica, it shows that a silica-supported gold-copper (1:1) ordered intermetallic compound structure is formed, and the platinum on the surface does not form a separate phase.

[0077] Figure 2 is the scanning transmission electron microscopy image with atomic resolution of platinum (Pt-AuCu) atomically dispersed on the surface of the gold-copper (1:1) intermetallic compound nanoparticles in Example 5. The intensity of individual atoms is stronger than that of surrounding atoms, indicating the presence of atomically dispersed Pt atoms.

[0078] Figure 3 in (a) is the scanning transmission electron microscopy image of platinum atomically dispersed on the surface of the gold-copper (1:1) intermetallic compound nanoparticles in Example 2, Figure 3 in (b)-(d) are the energy-dispersive X-ray spectroscopy maps of platinum atomically dispersed on the surface of the gold-copper (1:1) intermetallic compound nanoparticles in Example 2. The Au and Cu elements are evenly distributed, and the Pt element signal is weak and no obvious shell is formed, reflecting the property of atomic dispersion.

[0079] Figure 4 is the platinum (Pt-AuCu 3 / SiO 2) The X-ray diffraction (XRD) pattern, by comparison with the standard gold-copper (1:1) intermetallic compound and silica, indicates the formation of a silica-supported gold-copper (1:3) ordered intermetallic compound structure, and the platinum on the surface does not form a separate phase.

[0080] Figure 5 In (a), the cyclic voltammetry curve of pure Pt catalyzing formic acid oxidation is shown. Figure 5 In (b), the cyclic voltammetry curve of atomic-level dispersed platinum (Pt-AuCu) on the surface of the gold-copper (1:1) intermetallic compound nanoparticles in Examples 5 and 10 catalyzing formic acid oxidation is shown. The results indicate that the overpotential of the prepared catalyst (Pt-AuCu) for catalyzing formic acid oxidation decreases, and it has good selectivity and activity for directly catalyzing the oxidation of formic acid.

[0081] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation method of a supported single-atom alloy catalyst, characterized in that, it comprises the following steps: (1) Dissolve a gold salt and a non-noble metal salt in a solvent to obtain a salt solution, and disperse a support in the salt solution. The gold salt and the non-noble metal salt are adsorbed on the support. After the solvent is evaporated to dryness, a solid powder is obtained; the non-noble metal salt is a copper salt or a zinc salt; the atomic ratio of gold to copper in the gold salt and the copper salt is 1:(0.3 - 3); the atomic ratio of gold to zinc in the gold salt and the zinc salt is 1:(0.8 - 2); (2) Heat the solid powder once under a reducing atmosphere for reduction to obtain supported bimetallic nanoparticles; heat the supported bimetallic nanoparticles twice under a reducing atmosphere to order the bimetallic nanoparticles and form intermetallic compound nanoparticles; (3) Disperse the supported intermetallic compound nanoparticles in a solvent, add a third metal salt with a reduction potential between the two metals in the intermetallic compound for a displacement reaction, and then obtain the supported single-atom alloy catalyst after centrifugal separation and drying; the third metal salt is a salt containing a platinum group metal.

2. A preparation method of a supported single-atom alloy catalyst, characterized in that, it comprises the following steps: (1) Dissolve a gold salt and a non-noble metal salt in a solvent to obtain a salt solution, and disperse a support in the salt solution. The gold salt and the non-noble metal salt are adsorbed on the support. After the solvent is evaporated to dryness, a solid powder is obtained; the non-noble metal salt is a copper salt or a zinc salt; the atomic ratio of gold to copper in the gold salt and the copper salt is 1:(0.3 - 3); the atomic ratio of gold to zinc in the gold salt and the zinc salt is 1:(0.8 - 2); (2) Heat the solid powder once under a reducing atmosphere for reduction to obtain supported bimetallic nanoparticles; (3) Disperse the supported bimetallic nanoparticles in a solution containing tris(hydroxymethyl)aminomethane and dopamine hydrochloride to obtain a polydopamine-coated support with bimetallic nanoparticles loaded on the support; (4) Heat the bimetallic nanoparticles supported on the polydopamine-coated support twice under a reducing atmosphere to carbonize the polydopamine and order the bimetallic nanoparticles, and intermetallic compound nanoparticles are loaded on the support; (5) Disperse the supported intermetallic compound nanoparticles in a solvent, add a third metal salt with a reduction potential between the two metals in the intermetallic compound for a displacement reaction, and then obtain the supported single-atom alloy catalyst after centrifugal separation and drying; the third metal salt is a salt containing a platinum group metal.

3. The preparation method according to claim 1 or 2, characterized in that, the atomic ratio of the third metal to gold in the third metal salt is 1:(5 - 100).

4. The preparation method according to claim 1 or 2, characterized in that, the salt containing a platinum group metal is a platinum salt or a palladium salt.

5. The preparation method according to claim 1 or 2, characterized in that, The heating temperature of the primary heating is 150°C to 300°C, and the heating time is 2 - 5 h; the heating temperature of the secondary heat treatment is 700°C to 900°C, the heating time is 4 - 6 h, and the heating rate is 2 - 10 °C / min.

6. According to the preparation method described in claim 2, it is characterized in that the carrier is at least one of carbon black, Ketjen black, carbon nanotubes, spherical silica, nano-silica, and carbon formed by carbonization of polydopamine; when the carrier is spherical silica or nano-silica, after the secondary heat treatment in step (4), the silica is removed by a sodium hydroxide etching method.

7. A supported single-atom alloy catalyst obtained by the preparation method according to any one of claims 1 - 6.

8. According to the supported single-atom alloy catalyst described in claim 7, it is characterized in that the mass fraction of the noble metal element in the supported single-atom alloy catalyst is 20 - 60%.

9. An application of the supported single-atom alloy catalyst as described in claim 7 or 8, it is characterized in that it is used for the electrocatalytic formic acid oxidation reaction.

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