RuSe2-Pt bifunctional catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of hydrogen production through methanol electrolysis, and provides a preparation method of a RuSe2-Pt bifunctional catalyst. According to the preparation method, RuSe2 is grown on the carbon with the high specific surface area, so that the growth area is provided for ruthenium selenide, and meanwhile, the carbon with the high specific surface area can enhance the conductivity of the RuSe2-Pt bifunctional catalyst; then RuSe2 growing on carbon with a high specific surface area is used as a Pt carrier to provide a seed site so as to facilitate Pt loading, meanwhile, RuSe2 with an oxyphilic characteristic is used as a carrier to provide an oxygen-containing substance at a low potential through a ligand effect, the adsorption capacity of CO generated in an alcohol oxidation reaction process is reduced through downward movement of a d-band center, the utilization rate of Pt is increased, and the catalytic activity of the catalyst is improved. Further, the catalytic performance of the RuSe2-Pt bifunctional catalyst is enhanced; moreover, through the synergistic effect and electronic interaction of RuSe2 and Pt, the density of electrons around Pt nano-particles can be regulated and controlled, and the electro-catalytic performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic materials, and in particular to a RuSe2-Pt bifunctional catalyst and a preparation method and application thereof. Background Art

[0002] Due to the increasing demand for energy and the threat of environmental pollution to human sustainable development, the development of renewable and green energy has become an urgent requirement for future development. In recent years, hydrogen as a green and renewable energy has attracted widespread attention.

[0003] However, the current practical application of electrochemical water splitting to produce hydrogen is limited by the high overpotential of the oxygen evolution reaction at the anode. Compared with the theoretical potential of the oxygen evolution reaction from water splitting to produce hydrogen, the oxidation potential of methanol is lower. Therefore, methanol electrolysis that combines methanol oxidation and hydrogen evolution can achieve efficient hydrogen production. In the methanol oxidation reaction and hydrogen evolution reaction, platinum catalysts are currently considered to be the most effective single metal catalysts. However, platinum-based catalysts are expensive and are easily affected by harmful gases such as carbon monoxide during the electrooxidation process, which reduces the active sites available for methanol electrolysis and reduces the utilization rate of platinum. As a result, the catalytic activity and stability of platinum catalysts in catalyzing methanol electrolysis are low.

[0004] Therefore, how to improve the catalytic activity and stability of the catalyst for hydrogen production by methanol electrolysis has become a technical problem that needs to be urgently solved in this field. Summary of the Invention

[0005] The present invention aims to provide a RuSe2-Pt bifunctional catalyst and its preparation method and application. The RuSe2-Pt bifunctional catalyst provided by the present invention is applied to methanol electrolysis to produce hydrogen and has high catalytic activity and stability.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a RuSe2-Pt bifunctional catalyst, comprising the following steps:

[0008] 1) mixing high specific surface area carbon, a soluble ruthenium source and deionized water and freeze-drying the mixture to obtain a ruthenium source precursor;

[0009] 2) mixing the ruthenium source precursor obtained in step 1) with selenium powder and performing annealing treatment to obtain a ruthenium selenide precursor;

[0010] 3) The ruthenium selenide precursor obtained in step 2) is mixed with a reducing solvent and an H2PtCl6 aqueous solution and then subjected to a reduction reaction to obtain a RuSe2-Pt bifunctional catalyst.

[0011] Preferably, in step 1), the mass ratio of high specific surface area carbon to soluble ruthenium source is 10:(3-6).

[0012] Preferably, in step 1), the mass ratio of high specific surface area carbon to deionized water is 1:(400-600).

[0013] Preferably, the mass ratio of the high specific surface area carbon in step 1) to the selenium powder in step 2) is 5:(13-26).

[0014] Preferably, the temperature of the annealing treatment in step 2) is 350-600° C., and the annealing treatment time is 1-3 hours.

[0015] Preferably, in step 3), the volume ratio of the ruthenium selenide precursor to the reducing solvent is 4 mg: (5-10) mL.

[0016] Preferably, in step 3), the mass ratio of the ruthenium selenide precursor to Pt in the H2PtCl6 aqueous solution is 4:(0.5-2).

[0017] Preferably, the temperature of the reduction reaction in step 3) is 120-150° C., and the time of the reduction reaction is 3-6 hours.

[0018] The present invention also provides a RuSe2-Pt bifunctional catalyst prepared by the above preparation method, comprising high specific surface area carbon, RuSe2 grown on the surface of the high specific surface area carbon, and Pt nanoparticles loaded on the RuSe2.

[0019] The present invention also provides the use of the RuSe2-Pt bifunctional catalyst prepared by the above preparation method in hydrogen production by methanol electrolysis.

[0020] The present invention provides a preparation method of a RuSe2-Pt bifunctional catalyst, comprising the following steps: 1) mixing high specific surface area carbon, a soluble ruthenium source and deionized water, and then freeze-drying to obtain a ruthenium source precursor; 2) mixing the ruthenium source precursor obtained in step 1) with selenium powder, and then annealing to obtain a ruthenium selenide precursor; 3) mixing the ruthenium selenide precursor obtained in step 2) with a reducing solvent and an H2PtCl6 aqueous solution, and then performing a reduction reaction to obtain a RuSe2-Pt bifunctional catalyst. The present invention freeze-dries a mixture of high-specific-surface-area carbon, a soluble ruthenium source, and deionized water, thereby uniformly dispersing the soluble ruthenium source on the surface of the high-specific-surface-area carbon without destroying the morphology of the high-specific-surface-area carbon. The mixture is then mixed with selenium powder and annealed to react with the selenium powder to generate ruthenium selenide. The mixture is then mixed with a reducing solvent and an H2PtCl6 aqueous solution is added to enable Pt ions in the H2PtCl6 aqueous solution to undergo a reduction reaction with the reducing solvent, thereby loading the obtained Pt nanoparticles on the surface of the ruthenium selenide to obtain a RuSe2-Pt bifunctional catalyst. The present invention first grows RuSe2 on high-specific surface area carbon, and then uses the RuSe2 grown on the high-specific surface area carbon as a carrier of Pt nanoparticles. The high-specific surface area carbon provides sufficient growth area for ruthenium selenide, and the high-specific surface area carbon can enhance the conductivity of the prepared RuSe2-Pt bifunctional catalyst. RuSe2, as a carrier of Pt nanoparticles, provides a large number of seed sites, which is conducive to the loading of platinum nanoparticles. At the same time, RuSe2, which has an oxygen-philic property, can provide oxygen-containing substances at a low potential through a ligand effect as a carrier, and reduce the adsorption capacity of CO poisoning gas generated during the alcohol oxidation reaction by downward shifting the d-band center, thereby improving the utilization rate of the platinum nanoparticles and further enhancing the catalytic performance of the prepared RuSe2-Pt bifunctional catalyst. In addition, the component synergistic effect and electronic interaction of RuSe2 and Pt can regulate the electron density around the Pt nanoparticles, thereby improving the utilization rate and electrocatalytic performance of the Pt atoms. The results of the embodiment show that compared with graphene-supported platinum catalyst and commercial platinum-carbon catalyst, the RuSe2-Pt bifunctional catalyst prepared in the present invention can achieve a current density of 65 mA cm when catalyzing the acidic methanol oxidation to hydrogen. -2 , showing better catalytic activity; in the chronoamperometric test, the current density was still high after 7000s, showing better stability; in the HER performance test, the current density reached 10mA·cm -2The RuSe2-Pt bifunctional catalyst prepared by the present invention has a smaller overpotential than that of the platinum-carbon catalyst, and after 1000 CV cycles, the increase in the overpotential of the catalyst is negligible, indicating that the RuSe2-Pt bifunctional catalyst prepared by the present invention has better catalytic performance and stability; when catalyzing methanol electrolysis to produce hydrogen in an alkaline electrolyte, the RuSe2-Pt bifunctional catalyst prepared by the present invention still shows better catalytic activity and stability than the graphene-supported platinum catalyst and the commercial platinum-carbon catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 XRD patterns of the ruthenium selenide precursor, RuSe2-Pt bifunctional catalyst prepared in Example 1 of the present invention, and the Pt catalyst prepared in Comparative Example 1;

[0022] Figure 2 TEM image of the ruthenium selenide precursor prepared in Example 1 of the present invention;

[0023] Figure 3 TEM image of the RuSe2-Pt bifunctional catalyst prepared in Example 1 of the present invention;

[0024] Figure 4 TEM image of the Pt catalyst prepared in Comparative Example 1;

[0025] Figure 5 Cyclic voltammograms of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst in a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol;

[0026] Figure 6 Graphs showing chronoamperometric tests of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst in a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol;

[0027] Figure 7 HER performance diagram of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst in 0.5 mol / L sulfuric acid solution;

[0028] Figure 8 Polarization curves of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and a commercial platinum-carbon catalyst in 0.5 mol / L sulfuric acid solution;

[0029] Figure 9The electrolysis hydrogen production performance diagrams of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst in 0.5 mol / L sulfuric acid solution and a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol, respectively;

[0030] Figure 10 This is a chronoamperometric test curve of hydrogen production by electrolysis of the RuSe2-Pt bifunctional catalyst prepared in Example 1 in a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol;

[0031] Figure 11 Cyclic voltammograms of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst in a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol;

[0032] Figure 12 Graphs of chronoamperometric tests of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst in a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol;

[0033] Figure 13 HER performance diagram of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst in 1 mol / L potassium hydroxide solution;

[0034] Figure 14 Polarization curves of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and a commercial platinum-carbon catalyst in 1 mol / L potassium hydroxide solution;

[0035] Figure 15 The electrolysis hydrogen production performance diagrams of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst in 1 mol / L potassium hydroxide solution and 1 mol / L potassium hydroxide and 1 mol / L methanol mixed solution, respectively;

[0036] Figure 16 This is a chronoamperometric test curve of the RuSe2-Pt bifunctional catalyst prepared in Example 1 for hydrogen production by electrolysis in a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol. DETAILED DESCRIPTION

[0037] The present invention provides a method for preparing a RuSe2-Pt bifunctional catalyst, comprising the following steps:

[0038] 1) mixing high specific surface area carbon, a soluble ruthenium source and deionized water and freeze-drying the mixture to obtain a ruthenium source precursor;

[0039] 2) mixing the ruthenium source precursor obtained in step 1) with selenium powder and performing annealing treatment to obtain a ruthenium selenide precursor;

[0040] 3) The ruthenium selenide precursor obtained in step 2) is mixed with a reducing solvent and an H2PtCl6 aqueous solution and then subjected to a reduction reaction to obtain a RuSe2-Pt bifunctional catalyst.

[0041] The invention mixes high specific surface area carbon, a soluble ruthenium source and deionized water and then freeze-dries the mixture to obtain a ruthenium source precursor.

[0042] In the present invention, the mass ratio of the high surface area carbon to the soluble ruthenium source is preferably 10:(3-6), more preferably 10:5. By limiting the mass ratio of the high surface area carbon to the soluble ruthenium source, the present invention allows the soluble ruthenium source to grow more fully on the surface of the high surface area carbon.

[0043] In the present invention, the high surface area carbon refers to a carbon material having a large surface area. In the present invention, the high surface area carbon is preferably one of graphene nanosheets, Vulcan XC72 carbon black, carbon nanotubes, and porous carbon spheres. In the present invention, the soluble ruthenium source is preferably one of ruthenium trichloride, ruthenium acetate, and ruthenium acetylacetonate.

[0044] In the present invention, the mass ratio of the high specific surface area carbon to deionized water is preferably 1:(400-600), more preferably 1:500. By limiting the mass ratio of the high specific surface area carbon to deionized water, the present invention allows the high specific surface area carbon to be more fully dispersed in deionized water.

[0045] In the present invention, the mixing of the high surface area carbon and the soluble ruthenium source is preferably carried out under stirring. In the present invention, the stirring speed is preferably 500 to 700 r / s, and the stirring time is preferably 5 to 10 hours. The present invention does not particularly limit the stirring method, and any stirring method known in the art can be used. In the present invention, the stirring method is preferably magnetic stirring.

[0046] In the present invention, the freeze-drying temperature is preferably -20 to -40°C, more preferably -30°C; and the freeze-drying time is 24 to 48 hours, more preferably 36 hours. By limiting the freeze-drying temperature and time, the present invention can better protect the carbon material morphology from being destroyed.

[0047] After obtaining the ruthenium source precursor, the present invention mixes the ruthenium source precursor with selenium powder and then performs annealing treatment to obtain a ruthenium selenide precursor.

[0048] In the present invention, the mass ratio of the high specific surface area carbon to the selenium powder is preferably 5:(13-26), more preferably 5:(15-20). The present invention limits the mass ratio of the high specific surface area carbon to the selenium powder to ensure that the selenium powder can react more fully with the ruthenium source on the high specific surface area carbon.

[0049] In the present invention, the annealing treatment is preferably performed under a nitrogen or argon atmosphere. In the present invention, during the annealing treatment, the selenium powder reacts with the soluble ruthenium source on the ruthenium source precursor to generate ruthenium selenide, thereby obtaining a ruthenium selenide precursor. In the present invention, the annealing treatment temperature is preferably 350-600°C, more preferably 400-500°C; the annealing treatment time is preferably 1-3 hours, more preferably 2 hours. The present invention limits the annealing treatment temperature and time to ensure that the selenium powder and the soluble ruthenium source on the ruthenium source precursor react more fully to generate the ruthenium selenide precursor.

[0050] After obtaining the ruthenium selenide precursor, the present invention mixes the ruthenium selenide precursor with a reducing solvent and an H2PtCl6 aqueous solution and then performs a reduction reaction to obtain a RuSe2-Pt bifunctional catalyst.

[0051] In the present invention, the volume ratio of the ruthenium selenide precursor to the reducing solvent is preferably 4 mg:(5-10) mL, more preferably 4 mg:5 mL. The present invention limits the mass ratio of the ruthenium selenide precursor to the reducing solvent to ensure that the ruthenium selenide precursor is more evenly dispersed in the reducing solvent. In the present invention, the reducing solvent is preferably one of ethylene glycol, benzyl alcohol, methanol, and formic acid.

[0052] In the present invention, the mass ratio of the ruthenium selenide precursor to the Pt in the H2PtCl6 aqueous solution is preferably 4:(0.5-2), more preferably 4:1. The present invention limits the mass ratio of the ruthenium selenide precursor to the Pt in the H2PtCl6 aqueous solution to ensure that Pt can be more fully loaded on the ruthenium selenide precursor. In the present invention, the Pt content in the H2PtCl6 aqueous solution is preferably 20-40 mg / mL, more preferably 30 mg / mL.

[0053] In the present invention, the mixing of the ruthenium selenide precursor with the reducing solvent and the H2PtCl6 aqueous solution is preferably carried out by first mixing the ruthenium selenide precursor with the reducing solvent and then mixing with the H2PtCl6 aqueous solution. The present invention ensures that the ruthenium selenide precursor and the reducing solvent are mixed more fully by first mixing the ruthenium selenide precursor with the reducing solvent, so that subsequent Pt can be more fully loaded on the ruthenium selenide precursor. In the present invention, the mixing of the ruthenium selenide precursor with the reducing solvent and the H2PtCl6 aqueous solution is preferably carried out under stirring. In the present invention, the rotation speed of the stirring is preferably 500 to 700 r / s, and the time of magnetic stirring is preferably 5 to 10 hours.

[0054] In the present invention, the reduction reaction temperature is preferably 120-150°C, more preferably 130-140°C; and the reduction reaction time is preferably 3-6 hours, more preferably 4-5 hours. In the present invention, platinum ions are reduced to metallic platinum nanoparticles under the reducing action of the reducing solvent during the reduction reaction and are loaded onto the surface of the ruthenium selenide precursor. By controlling the temperature and time of the reduction reaction, the present invention can effectively reduce the platinum ions to platinum metal nanoparticles.

[0055] In the present invention, the reduction reaction method is preferably a microwave high-pressure treatment method. In the present invention, the power of the microwave high-pressure treatment is preferably 600-900W, more preferably 600-700W; the pressure of the microwave high-pressure treatment is preferably 3-5MPa, more preferably 4MPa. The present invention limits the temperature and pressure of the microwave high-pressure treatment to ensure that the platinum ions are better reduced to platinum metal nanoparticles. The present invention has no special restrictions on the equipment for the microwave high-pressure treatment, and microwave high-pressure treatment equipment well known in the art can be used. In the present invention, the microwave high-pressure treatment equipment is preferably a solid-liquid phase microwave synthesizer.

[0056] After the reduction reaction is completed, the present invention preferably cools the product of the reduction reaction, filters it, washes it with deionized water, and dries it in sequence to obtain a RuSe2-Pt bifunctional catalyst.

[0057] In the present invention, the cooling is preferably natural cooling to room temperature. The present invention has no special restrictions on the operations of filtration, deionized water washing and drying, and the filtration, deionized water washing and drying operations well known in the art can be used. In the present invention, the number of deionized water washings is preferably 3 to 5 times. In the present invention, the drying is preferably vacuum drying. In the present invention, the drying temperature is preferably 60 to 80°C; the drying time is preferably 10 to 12 hours. The present invention has no special restrictions on the drying equipment, and the drying equipment well known in the art can be used. In the present invention, the drying equipment is preferably a vacuum drying oven.

[0058] The present invention freeze-dries a mixture of high-specific-surface-area carbon, a soluble ruthenium source, and deionized water, thereby uniformly dispersing the soluble ruthenium source on the surface of the high-specific-surface-area carbon without destroying the morphology of the high-specific-surface-area carbon. The mixture is then mixed with selenium powder and annealed to react with the selenium powder to generate ruthenium selenide. The mixture is then mixed with a reducing solvent and an H2PtCl6 aqueous solution is added to enable Pt ions in the H2PtCl6 aqueous solution to undergo a reduction reaction with the reducing solvent, thereby loading the obtained Pt nanoparticles on the surface of the ruthenium selenide to obtain a RuSe2-Pt bifunctional catalyst.

[0059] The present invention also provides a RuSe2-Pt bifunctional catalyst prepared by the above preparation method, comprising high specific surface area carbon, RuSe2 grown on the surface of the high specific surface area carbon, and Pt nanoparticles loaded on the RuSe2.

[0060] The present invention first grows RuSe2 on high-specific surface area carbon, and then uses the RuSe2 grown on the high-specific surface area carbon as a carrier of Pt nanoparticles. The high-specific surface area carbon provides sufficient growth area for ruthenium selenide, and the high-specific surface area carbon can enhance the conductivity of the prepared RuSe2-Pt bifunctional catalyst. RuSe2, as a carrier of Pt nanoparticles, provides a large number of seed sites, which is conducive to the loading of platinum nanoparticles. At the same time, RuSe2, which has an oxygen-philic property, can provide oxygen-containing substances at a low potential through a ligand effect as a carrier, and reduce the adsorption capacity of CO poisoning gas generated during the alcohol oxidation reaction by downward shifting the d-band center, thereby improving the utilization rate of the platinum nanoparticles and further enhancing the catalytic performance of the prepared RuSe2-Pt bifunctional catalyst. In addition, the component synergistic effect and electronic interaction of RuSe2 and Pt can regulate the electron density around the Pt nanoparticles, thereby improving the utilization rate and electrocatalytic performance of the Pt atoms.

[0061] The present invention also provides the use of the RuSe2-Pt bifunctional catalyst prepared by the above preparation method in the production of hydrogen by methanol electrolysis. In the present invention, the use of the RuSe2-Pt bifunctional catalyst in the production of hydrogen by methanol electrolysis preferably includes the use of the RuSe2-Pt bifunctional catalyst in the production of hydrogen by methanol electrolysis in a catalytic acidic electrolyte and a catalytic alkaline electrolyte.

[0062] In an embodiment of the present invention, the application of the RuSe2-Pt bifunctional catalyst in catalytic methanol electrolysis to hydrogen production in an acidic electrolyte is preferably:

[0063] The methanol oxidation reaction in catalytic acidic electrolyte was carried out on an electrochemical workstation using a standard three-electrode system at room temperature (25°C). The electrolyte was a mixed solution of 1 mol / L methanol and 0.5 mol / L sulfuric acid. The electrolytes for the catalytic electrolysis of methanol to hydrogen in acidic electrolyte were 0.5 mol / L sulfuric acid solution and a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol, respectively. The glassy carbon electrode surface after alumina polishing was used as the working electrode, the saturated calomel electrode (SCE) was used as the reference electrode, and the carbon rod was used as the counter electrode.

[0064] In an embodiment of the present invention, the application of the RuSe2-Pt bifunctional catalyst in catalyzing the electrolysis of methanol to produce hydrogen in an alkaline electrolyte is preferably:

[0065] The catalytic oxidation reaction of methanol in alkaline electrolyte was carried out on an electrochemical workstation using a standard three-electrode system at room temperature (25°C). The electrolyte was a mixed solution of 1 mol / L methanol and 1 mol / L potassium hydroxide. The electrolytes for the catalytic electrolysis of methanol to hydrogen in alkaline electrolyte were 1 mol / L potassium hydroxide solution and a mixed solution of 1 mol / L methanol and 1 mol / L potassium hydroxide, respectively. The glassy carbon electrode surface after alumina polishing was used as the working electrode, the saturated calomel electrode (SCE) was used as the reference electrode, and the carbon rod was used as the counter electrode.

[0066] The RuSe2-Pt bifunctional catalyst prepared by the present invention can achieve a current density of 65 mA cm when catalyzing the acidic methanol oxidation to produce hydrogen. -2 ~, showing better catalytic activity; in the chronoamperometric test, the current density was still high after 7000s, showing better stability; in the HER performance test, the current density reached 10mA·cm -2 The RuSe2-Pt bifunctional catalyst prepared by the present invention has a smaller overpotential than that of the platinum-carbon catalyst, and after 1000 CV cycles, the increase in the overpotential of the catalyst is negligible, indicating that the RuSe2-Pt bifunctional catalyst prepared by the present invention has better catalytic performance and stability; when catalyzing methanol electrolysis to produce hydrogen in an alkaline electrolyte, the RuSe2-Pt bifunctional catalyst prepared by the present invention still shows better catalytic activity and stability than the graphene-supported platinum catalyst and the commercial platinum-carbon catalyst.

[0067] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

[0068] Example 1

[0069] A method for preparing a RuSe2-Pt bifunctional catalyst comprises the following steps:

[0070] 1) mixing 100 mg of graphene nanosheets, 1 mL of a ruthenium trichloride aqueous solution having a ruthenium content of 30 mg / mL, and 50 mL of deionized water, magnetically stirring at 600 r / s for 6 hours, and then freeze-drying at -40°C for 30 hours to obtain a ruthenium source precursor; the mass ratio of the graphene to the ruthenium trichloride in the ruthenium trichloride aqueous solution is 10:3, and the mass ratio of the graphene nanosheets to deionized water is 1:500;

[0071] 2) mixing the ruthenium source precursor obtained in step 1) with 260 mg of selenium powder, and annealing the mixture at 450° C. for 2 h in a nitrogen atmosphere to obtain a ruthenium selenide precursor, designated as RuSe2-Gr; the mass ratio of the graphene nanosheets to the selenium powder was 5:13;

[0072] 3) 40 mg of the ruthenium selenide precursor obtained in step 2) was mixed with 50 mL of ethylene glycol, and then mixed with 330 μL of an H2PtCl6 aqueous solution with a pt content of 30 mg / mL and magnetically stirred at 600 r / s for 30 min. The mixture was transferred to a solid-liquid phase microwave synthesizer with a power of 800 W and a pressure of 3 MPa, and subjected to microwave high-pressure treatment at 140°C for 4 hours for a reduction reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, filtered, washed with deionized water 5 times, and vacuum dried in a vacuum drying oven at 60°C for 12 hours to obtain a RuSe2-Pt bifunctional catalyst, recorded as Pt-RuSe2 / Gr; the mass ratio of the ruthenium selenide precursor to the volume of ethylene glycol was 4 mg:5 mL; the mass ratio of the ruthenium selenide precursor to Pt in the H2PtCl6 aqueous solution was 4:1.

[0073] Comparative Example 1

[0074] A method for preparing a platinum catalyst comprises the following steps:

[0075] 40 mg of graphene nanosheets were mixed with 50 mL of ethylene glycol solution, and then mixed with 330 μL of H2PtCl6 aqueous solution with a Pt content of 30 mg / mL and magnetically stirred at 600 r / s for 30 min. The mixture was transferred to a solid-liquid phase microwave synthesizer with a power of 800 W and a pressure of 3 MPa, and subjected to microwave high-pressure treatment at 140°C for 4 hours for reduction reaction. After the reaction was completed, the mixture was naturally cooled to room temperature, filtered, washed with deionized water 5 times, and vacuum dried in a vacuum drying oven at 60°C for 12 hours to obtain a platinum catalyst, recorded as Pt / Gr.

[0076] The present invention analyzed the ruthenium selenide precursor, RuSe2-Pt bifunctional catalyst and platinum catalyst prepared in Example 1 by powder X-ray diffractometer (XRD). Figure 1 As shown in the figure, it can be seen that the corresponding ruthenium selenide precursor, RuSe2-Pt bifunctional catalyst and platinum catalyst were prepared in both Example 1 and Comparative Example 1.

[0077] The ruthenium selenide precursor, RuSe2-Pt bifunctional catalyst and platinum catalyst prepared in Example 1 were analyzed by transmission electron microscopy. Figures 2-4 As shown. Figure 2 It can be seen that pure phase ruthenium selenide nanocrystals are prepared in step 2) of Example 1 of the present invention, and ruthenium selenide is evenly distributed on the graphene nanosheets; Figure 3It can be seen that the average particle size of the RuSe2-Pt bifunctional catalyst particles prepared in Example 1 of the present invention is increased, indicating that platinum nanoparticles are successfully loaded on ruthenium selenide, and the platinum nanoparticles loaded on ruthenium selenide are evenly dispersed on the surface of the graphene nanosheets; Figure 4 It can be seen that the platinum catalyst prepared in Comparative Example 1 formed clusters with uneven particle sizes. Figure 3 and Figure 4 By comparison, it can be seen that when ruthenium selenide nanocrystals grown on graphene nanosheets are used as carriers of platinum nanoparticles, the platinum nanoparticles can be evenly grown on the nanosheets, effectively improving the dispersion and stability of the catalyst.

[0078] Application Example 1 and Comparative Application Example 1

[0079] Application of RuSe2-Pt bifunctional catalyst for hydrogen production by methanol electrolysis in catalytic acidic electrolyte:

[0080] The methanol oxidation reaction in the catalytic acidic electrolyte was carried out on an electrochemical workstation using a standard three-electrode system at room temperature (25°C). The electrolyte was a mixed solution of 1 mol / L methanol and 0.5 mol / L sulfuric acid. The electrolytes for the catalytic electrolysis of methanol to hydrogen in the acidic electrolyte were 0.5 mol / L sulfuric acid solution and a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol, respectively. The surface of the glassy carbon electrode after alumina polishing was used as the working electrode, the saturated calomel electrode (SCE) was used as the reference electrode, and the carbon rod was used as the counter electrode. The specific process was as follows: 2.5 mg of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the platinum catalyst prepared in Comparative Example 1 were added to a mixed solution of 475 μL ethanol and 25 μL Nafion perfluorosulfonic acid polymer solution, respectively, and ultrasonically dispersed to obtain a well-dispersed catalyst ink. 10 μL of the catalyst ink was dripped onto the surface of the working electrode and dried.

[0081] The present invention adopts cyclic voltammetry to perform cyclic voltammetry scanning on the RuSe2-Pt bifunctional catalyst prepared in Example 1, the platinum catalyst prepared in Comparative Example 1 and the commercial platinum-carbon catalyst at a scanning rate of 50 mV / s between -0.2 and 1 V, and obtains cyclic voltammetry curves of the three in a mixed solution of 1 mol / L methanol and 0.5 mol / L sulfuric acid, as shown in FIG. Figure 5 As shown in the figure, it can be seen that compared with platinum catalysts and commercial platinum-carbon catalysts, the RuSe2-Pt bifunctional catalyst of the present invention has higher catalytic activity when catalyzing acidic methanol oxidation reaction.

[0082] The present invention performs a 7000-second constant current timing test on the RuSe2-Pt bifunctional catalyst prepared in Example 1, the platinum catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst at a potential of 0.6 V vs. SCE, and obtains a chronoamperometric test curve of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and the commercial platinum-carbon catalyst under the conditions of a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol, as shown in FIG. Figure 6 As shown in the figure, it can be seen that compared with platinum catalysts and commercial platinum-carbon catalysts, the RuSe2-Pt bifunctional catalyst of the present invention has higher stability when catalyzing acidic methanol oxidation reaction.

[0083] The present invention performs HER testing on the RuSe2-Pt bifunctional catalyst prepared in Example 1 and a commercial platinum-carbon electrode in a catalytic acidic electrolyte, and uses cyclic voltammetry to perform cyclic voltammetry scanning between 0 and -0.3 V at a scan rate of 5 mV / s to obtain the HER performance graph of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon electrode under 0.5 mol / L sulfuric acid solution conditions, as shown in FIG. Figure 7 As shown in the figure, when the current density of the catalytic hydrogen evolution reaction reaches 10 mA cm -2 When the catalyst prepared in Example 1 has a smaller overpotential than that of the platinum-carbon catalyst, it is shown that the RuSe2-Pt bifunctional catalyst prepared in the present invention has a higher catalytic activity when catalyzing the acidic methanol oxidation reaction.

[0084] The present invention carried out 1000 CV cycles on the RuSe2-Pt bifunctional catalyst prepared in Example 1, and obtained polarization curves of the RuSe2-Pt bifunctional catalyst prepared in Example 1 before and after 1000 cycles in 0.5 mol / L sulfuric acid solution, as shown in FIG. Figure 8 As shown in the figure, it can be seen that after 1000 CV cycles, the increase in the overpotential of the RuSe2-Pt bifunctional catalyst prepared in Example 1 is negligible, indicating that the RuSe2-Pt bifunctional catalyst prepared in the present invention has good stability.

[0085] The present invention electrolyzes hydrogen in a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol. Cyclic voltammetry is performed between 0 and 1.3 V at a scan rate of 5 mV / s to obtain the electrolytic hydrogen production performance graphs of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst under the conditions of 0.5 mol / L sulfuric acid solution and 0.5 mol / L sulfuric acid and 1 mol / L methanol mixed solution, respectively. Figure 9 As shown in the figure, in 0.5 mol / L sulfuric acid solution, when the current density reaches 10 mA cm -2When the potential required by the RuSe2-Pt bifunctional catalyst prepared in Example 1 is less than that of the platinum carbon catalyst, and after adding the methanol solution, the RuSe2-Pt bifunctional catalyst prepared in Example 1 has a current density of 10 mA·cm -2 The potential is the smallest when , indicating that the RuSe2-Pt bifunctional catalyst prepared in the present invention has higher catalytic activity when catalyzing acidic electrolysis to produce hydrogen.

[0086] The present invention performs a 24-hour constant current timing test on the RuSe2-Pt bifunctional catalyst prepared in Example 1 at a potential of -0.275V vs. SCE, and obtains a chronoamperometric test curve of the RuSe2-Pt bifunctional catalyst prepared in Example 1 under the conditions of a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol, as shown in FIG. Figure 10 As shown in the figure, the RuSe2-Pt bifunctional catalyst prepared in Example 1 has only a small current density decay after 12 hours of chronoamperometry, indicating that the catalyst prepared in Example 1 has good stability when catalyzing the electrolysis of a mixed solution of 0.5 mol / L sulfuric acid and 1 mol / L methanol to produce hydrogen.

[0087] Application Example 2 and Comparative Application Example 2

[0088] Application of RuSe2-Pt bifunctional catalyst for hydrogen production by methanol electrolysis in catalytic alkaline electrolyte:

[0089] The catalytic oxidation reaction of methanol in an alkaline electrolyte was carried out on an electrochemical workstation using a standard three-electrode system at room temperature (25°C). The electrolyte was a mixed solution of 1 mol / L methanol and 1 mol / L potassium hydroxide. The electrolytes for the catalytic electrolysis of methanol to hydrogen in an acidic electrolyte were a 1 mol / L potassium hydroxide solution and a mixed solution of 1 mol / L methanol and 1 mol / L potassium hydroxide, respectively. A glassy carbon electrode surface polished with alumina was used as the working electrode, a saturated calomel electrode (SCE) was used as the reference electrode, and a carbon rod was used as the counter electrode. The specific process was as follows: 2.5 mg of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the platinum catalyst prepared in Comparative Example 1 were added to a mixed solution of 475 μL of ethanol and 25 μL of Nafion perfluorosulfonic acid polymer solution, respectively, and ultrasonically dispersed to obtain a well-dispersed catalyst ink. 10 μL of the catalyst ink was dripped onto the surface of the working electrode and dried.

[0090] The present invention adopts cyclic voltammetry to perform cyclic voltammetry scanning on the RuSe2-Pt bifunctional catalyst prepared in Example 1, the platinum catalyst prepared in Comparative Example 1, and the commercial platinum-carbon catalyst at a scanning rate of 50 mV / s between -1 and 0.2 V, and obtains cyclic voltammetry curves of the three in a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol, as shown in FIG. Figure 11 As shown in the figure, it can be seen that compared with platinum catalysts and commercial platinum-carbon catalysts, the RuSe2-Pt bifunctional catalyst of the present invention has higher catalytic activity when catalyzing alkaline methanol oxidation reaction.

[0091] The present invention performs a 7000-second constant current timing test on the RuSe2-Pt bifunctional catalyst prepared in Example 1, the platinum catalyst prepared in Comparative Example 1, and a commercial platinum-carbon catalyst at a potential of -0.3 V vs. SCE, and obtains a chronoamperometric test curve of the RuSe2-Pt bifunctional catalyst prepared in Example 1, the Pt catalyst prepared in Comparative Example 1, and the commercial platinum-carbon catalyst under the conditions of a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol, as shown in FIG. Figure 12 As shown in the figure, it can be seen that compared with platinum catalysts and commercial platinum-carbon catalysts, the RuSe2-Pt bifunctional catalyst of the present invention has higher stability when catalyzing alkaline methanol oxidation reaction.

[0092] The present invention performs HER testing on the RuSe2-Pt bifunctional catalyst prepared in Example 1 and a commercial platinum-carbon electrode in a catalytic acidic electrolyte. Cyclic voltammetry is used to perform cyclic voltammetry scanning between 0 and -0.3 VV at a scan rate of 5 mV / s to obtain a HER performance graph of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon electrode under 1 mol / L potassium hydroxide solution, as shown in FIG. Figure 13 As shown in the figure, when the current density of the catalytic hydrogen evolution reaction reaches 10 mA cm -2 When the overpotential of the catalyst prepared in Example 1 is smaller than that of the platinum-carbon catalyst, it is shown that the RuSe2-Pt bifunctional catalyst prepared in the present invention has higher catalytic activity when catalyzing the alkaline methanol oxidation reaction.

[0093] The present invention carried out 1000 CV cycles on the RuSe2-Pt bifunctional catalyst prepared in Example 1, and obtained polarization curves of the RuSe2-Pt bifunctional catalyst prepared in Example 1 before and after 1000 cycles in 1 mol / L potassium hydroxide solution, as shown in FIG. Figure 14 As shown in the figure, it can be seen that after 1000 CV cycles, the increase in the overpotential of the RuSe2-Pt bifunctional catalyst prepared in Example 1 is negligible, indicating that the RuSe2-Pt bifunctional catalyst prepared in the present invention has good stability.

[0094] The present invention electrolyzes hydrogen in a mixed solution of 1 mol / L methanol and 1 mol / L potassium hydroxide, and cyclic voltammetry is used to perform cyclic voltammetry scanning between 0 and 1.3 V at a scanning rate of 5 mV / s. The electrolytic hydrogen production performance graphs of the RuSe2-Pt bifunctional catalyst prepared in Example 1 and the commercial platinum-carbon catalyst in the conditions of 1 mol / L potassium hydroxide solution and 1 mol / L potassium hydroxide and 1 mol / L methanol mixed solution are obtained, as shown in FIG. Figure 15 As shown in the figure, in a 1 mol / L potassium hydroxide solution, when the current density reaches 10 mA cm -2 When the potential required by the RuSe2-Pt bifunctional catalyst prepared in Example 1 is less than that of the platinum carbon catalyst, and after adding the methanol solution, the RuSe2-Pt bifunctional catalyst prepared in Example 1 has a current density of 10 mA·cm -2 The potential is the smallest when , indicating that the RuSe2-Pt bifunctional catalyst prepared in the present invention has higher catalytic activity when catalyzing alkaline electrolysis to produce hydrogen.

[0095] The present invention performs a 12-hour constant current timing test on the RuSe2-Pt bifunctional catalyst prepared in Example 1 at a potential of -0.282 V vs. SCE, and obtains a chronoamperometric test curve of the RuSe2-Pt bifunctional catalyst prepared in Example 1 under the conditions of a 1 mol / L potassium hydroxide and 1 mol / L methanol mixed solution, as shown in FIG. Figure 16 As shown in the figure, the RuSe2-Pt bifunctional catalyst prepared in Example 1 has only a small current density decay after 12 hours of chronoamperometry, indicating that the catalyst prepared in Example 1 has good stability when catalyzing the electrolysis of a mixed solution of 1 mol / L potassium hydroxide and 1 mol / L methanol to produce hydrogen.

[0096] It can be seen from the above examples and comparative examples that the RuSe2-Pt bifunctional catalyst provided by the present invention has good catalytic activity and good stability.

[0097] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a RuSe2-Pt bifunctional catalyst, comprising the following steps: 1) mixing high specific surface area carbon, a soluble ruthenium source and deionized water and freeze-drying the mixture to obtain a ruthenium source precursor; 2) mixing the ruthenium source precursor obtained in step 1) with selenium powder and performing annealing treatment to obtain a ruthenium selenide precursor; 3) The ruthenium selenide precursor obtained in step 2) is mixed with a reducing solvent and an H2PtCl6 aqueous solution and then subjected to a reduction reaction to obtain a RuSe2-Pt bifunctional catalyst.

2. The preparation method according to claim 1, characterized in that In the step 1), the mass ratio of the high specific surface area carbon to the soluble ruthenium source is 10:(3-6).

3. The preparation method according to claim 1, characterized in that In the step 1), the mass ratio of the high specific surface area carbon to deionized water is 1:(400-600).

4. The preparation method according to claim 1, characterized in that The mass ratio of the high specific surface area carbon in step 1) to the selenium powder in step 2) is 5:(13-26).

5. The preparation method according to claim 1, characterized in that The annealing temperature in step 2) is 350-600° C., and the annealing time is 1-3 hours.

6. The preparation method according to claim 1, characterized in that In the step 3), the volume ratio of the ruthenium selenide precursor to the reducing solvent is 4 mg: (5-10) mL.

7. The preparation method according to claim 1, characterized in that In the step 3), the mass ratio of the ruthenium selenide precursor to Pt in the H2PtCl6 aqueous solution is 4:(0.5-2).

8. The preparation method according to claim 1, characterized in that The temperature of the reduction reaction in step 3) is 120-150° C., and the time of the reduction reaction is 3-6 hours.

9. The RuSe2-Pt bifunctional catalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The RuSe2-Pt bifunctional catalyst comprises high specific surface area carbon, RuSe2 grown on the surface of the high specific surface area carbon, and Pt nanoparticles supported on the RuSe2.

10. Use of the RuSe2-Pt bifunctional catalyst according to claim 9 in hydrogen production by methanol electrolysis.

Images