Synthesis method of in-situ carbon-loaded osmium-platinum single-phase solid solution nano-alloy catalyst and application of nano-alloy catalyst in hydrogen evolution reaction

Abstract

The invention discloses a synthesis method of an in-situ carbon-loaded osmium-platinum single-phase solid solution nano-alloy catalyst and application of the nano-alloy catalyst in a hydrogen evolution reaction, and solves the technical problems that when an existing osmium-platinum alloy catalyst is used, the loading process is tedious and time-consuming, and the catalytic performance becomes poor due to non-uniform loading. The method comprises the following steps: respectively weighing an osmium compound and a platinum compound, mixing the osmium compound and the platinum compound, and adding the mixture into a polyol solvent until the mixture is completely dissolved to obtain a precursor solution; the preparation method comprises the following steps: preparing a carbon carrier, adding the carbon carrier into a polyol solvent until the carbon carrier is completely dissolved to obtain a carrier solution, and heating the carrier solution to 150-300 DEG C; in an inert atmosphere, adding the precursor solution into the heated carrier solution within two minutes, uniformly stirring, and preserving heat to obtain a mixed solution; and sequentially washing, centrifuging and drying to obtain the in-situ carbon loaded osmium-platinum solid solution nano-alloy catalyst. The method is simple in synthesis and high in synthesis efficiency, and the catalyst which is uniformly dispersed in a loaded state can be obtained.

Description

Technical Field

[0001] The present invention relates to a method for preparing a nano alloy catalyst in a non-mutually soluble alloy system, and in particular to a method for synthesizing an in-situ carbon-supported osmium platinum single-phase solid solution nano alloy catalyst and its application in a hydrogen evolution reaction. Background Art

[0002] The hydrogen evolution reaction (HER) plays a key role in electrocatalytic hydrogen production technologies using renewable energy sources, such as wind and photovoltaic power. Platinum-based catalysts are considered the best catalysts for the HER. Due to the high cost of platinum and the relatively low cost of osmium, and the fact that the introduction of osmium can modulate the electronic structure of platinum and optimize the adsorption properties of reaction intermediates, osmium-platinum alloy catalysts have attracted attention for their excellent activity in the HER, becoming a potential alternative to platinum-based catalysts.

[0003] Currently, osmium platinum alloy catalysts can be used in the oxygen reduction reaction (ORR) at the cathode in fuel cells, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water electrolysis, etc. They can also be used as components of three-way catalysts (TWCs) to promote the reaction of nitrogen oxides, carbon monoxide and hydrocarbons in automobile exhaust treatment, thereby purifying the air. However, in practical applications, existing osmium platinum alloy catalysts must first be loaded on a carrier to improve the catalytic effect. The loading method generally involves rotary evaporation, ultrasonic treatment and grinding, and the loading process is cumbersome and time-consuming. In addition, existing loading methods often make it difficult to evenly disperse the catalyst on the carrier, resulting in poor catalytic performance. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems that the loading process of existing osmium platinum alloy catalysts is cumbersome and time-consuming when used, and the catalytic performance deteriorates due to uneven loading, and to provide a method for synthesizing an in-situ carbon-supported osmium platinum single-phase solid solution nanoalloy catalyst and its application in hydrogen evolution reaction.

[0005] To achieve the above objectives, the technical solutions provided by the present invention are:

[0006] A method for synthesizing an in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst is characterized in that it comprises the following steps:

[0007] Step 1: Weigh an osmium compound and a platinum compound separately, mix the two, and add them to a polyol solvent until they are completely dissolved to obtain a precursor solution; the molar ratio of the osmium compound to the platinum compound is 10-70:30-90, and the total molar amount of the osmium element and the platinum element in the precursor solution is 0.2 mmol;

[0008] Step 2: preparing a carbon support and adding it to a polyol solvent until it is completely dissolved to obtain a support solution, and then heating the support solution to 150-300° C.; the mass of the carbon support is 2-99 times the total mass of the osmium element and the platinum element;

[0009] Step 3: Under an inert atmosphere, add the precursor solution to the heated carrier solution within two minutes, stir evenly, and then heat and react to obtain a mixed solution;

[0010] Step 4: Wash, centrifuge and dry the mixed solution in sequence to obtain an in-situ carbon-supported osmium-platinum solid solution nano-alloy catalyst.

[0011] Furthermore, in step 1, the osmium compound is selected from one or more of potassium hexachloroosmate, osmium (III) chloride hydrate, ammonium chloroosmate, sodium hexachloroosmium (IV) dihydrate, triosmium dodecacarbonyl, bis(cyclopentadienyl)osmium, and potassium osmate dihydrate;

[0012] The platinum compound is selected from one or more of potassium chloroplatinate, chloroplatinic acid hexahydrate, platinum tetrachloride, sodium chloroplatinite, sodium hexachloroplatinate, tetrachloroplatinum, tetraammineplatinate, cisplatin, ammonium chloroplatinate, potassium chloroplatinite, tetraammineplatinum nitrate, potassium tetranitroplatinate (II), potassium trichloroammineplatinate (II), and tetraammineplatinum chloride hydrate.

[0013] Furthermore, in step 2, after the carbon support is dissolved in the polyol solvent, liquid nitrogen is used for degassing three times to obtain a support solution.

[0014] Furthermore, in step 2, the carbon carrier is selected from one of acetylene black carrier, carbon nanotube carrier, mesoporous carbon carrier, and carbon aerogel carrier.

[0015] Furthermore, in step 2, the carrier solution is heated to 230°C.

[0016] Furthermore, in step 1 and step 2, the polyol solvent is any one of diethylene glycol, methanol, ethanol, n-propanol, isopropanol, n-butanol, pentanol, hexanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, dibutylene glycol, tributylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, butylene glycol monomethyl ether, butylene glycol monoethyl ether, glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol or oleylamine.

[0017] Furthermore, in step 3, the insulation reaction time is 5 minutes.

[0018] At the same time, the present invention also provides an in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst, which is special in that it is prepared by the above-mentioned synthesis method of the in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst, and its chemical formula is Fcc-Os x Pt 1-x / C, wherein 0<x<1, Fcc represents a face-centered cubic structure, Os represents an osmium element, Pt represents a platinum element, and C represents a carbon support.

[0019] Furthermore, the chemical formula is Fcc-Os 0.3 Pt 0.7 / C.

[0020] In addition, the present invention also provides an application of the above-mentioned in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst in the electrocatalysis of hydrogen evolution reaction.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention first prepares a precursor solution, then prepares a carrier solution, and then adds the precursor solution to the heated carrier solution to prepare an in-situ carbon-supported osmium platinum single-phase solid solution nanoalloy catalyst. This method overcomes the shortcomings of traditional synthesis methods and adopts a one-step synthesis method to simultaneously achieve phase control of the osmium platinum solid solution nanoalloy catalyst. The synthesis method is simple and has high synthesis efficiency, and a catalyst with uniform dispersion in the supported state can be obtained.

[0023] 2. In the synthesis process of the present invention, no protective agent is required, thereby greatly simplifying the post-synthesis process and also eliminating the influence of the protective agent on the catalytic activity of the catalyst.

[0024] 3. The catalyst prepared by the present invention can be used as a substitute for platinum-based catalysts, solving the problem of high prices of platinum-based catalysts.

[0025] 4. The catalyst prepared by the present invention has better catalytic activity for hydrogen evolution reaction than platinum, especially Fcc-Os 0.3 Pt 0.7 / C, its η in 0.5M H2SO4 10 It is only 1.0 mV, which is much better than the existing Pt-based catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 These are XRPD measurement results of the catalysts obtained in Examples 1, 2, 3, and 4 of the present invention and Comparative Examples 1 and 2.

[0027] Figure 2 The Fcc-Os obtained in Example 2 of the present invention 0.3 Pt 0.7 / CResults after Rietveld refinement at 303K.

[0028] Figure 3 The relationship between the ratios of Pt and Os of the catalysts obtained in Examples 1, 2, 3, and 4 of the present invention and Comparative Examples 1 and 2 as measured by XRF and EDX is shown.

[0029] Figure 4 Fcc-Os obtained in Example 2 of the present invention 0.3 Pt 0.7 HAADF-STEM image of / C; where:

[0030] Figure a is the original HAADF-STEM image;

[0031] Figure b is the STEM-energy dispersive X-ray distribution diagram of osmium;

[0032] Figure c is the STEM-energy dispersive X-ray distribution diagram of platinum element;

[0033] Figure d shows Fcc-Os 0.3 Pt 0.7 Overlay of the distribution of osmium and platinum in / C.

[0034] Figure 5 This is a comparison chart of the hydrogen evolution reaction activity of the catalysts obtained in Examples 1, 2, 3, and 4 of the present invention and Comparative Examples 1 and 2 in 0.5 M H2SO4; wherein:

[0035] Figure a is a comparison of the hydrogen evolution reaction activity polarization curves of various catalysts;

[0036] Figure b shows the 10 mA·cm -2 (η 10 ) and 20 mA·cm -2 (η 20 ) overpotential comparison diagram;

[0037] Figure c is a comparison of the mass activities of each catalyst at overpotentials of 10 mV and 20 mV;

[0038] Figure d is the Tafel comparison diagram of each catalyst.

[0039] Figure 6 This is a comparison chart of the hydrogen evolution reaction activity of the catalysts obtained in Examples 1, 2, 3, and 4 of the present invention and Comparative Examples 1 and 2 in 1M KOH in Experimental Example 2; wherein:

[0040] Figure a is a comparison of the hydrogen evolution reaction activity polarization curves of various catalysts;

[0041] Figure b shows the 10 mA·cm -2 (η10 ) and 20 mA·cm -2 (η 20 ) overpotential comparison diagram;

[0042] Figure c is a comparison of the mass activities of each catalyst at overpotentials of 10 mV and 20 mV;

[0043] Figure d is the Tafel comparison diagram of each catalyst. DETAILED DESCRIPTION

[0044] Inventive concept: In the field of catalysis, in order to load an osmium platinum alloy catalyst on a carrier material, it is generally necessary to perform loading steps such as rotary evaporation, ultrasonic treatment and grinding. However, this method is difficult to achieve uniform dispersion of nanoparticles on the carrier. The present application synthesizes an osmium platinum solid solution alloy catalyst containing a carrier, which can further improve its activity in the hydrogen evolution reaction. The reason is that the osmium platinum alloy with a single-phase face-centered cubic structure can expose a large number of densely packed (111) crystal planes, which will provide very close HH binding sites, thereby further shortening the time for hydrogen formation during the hydrogen evolution reaction. However, at present, an osmium platinum alloy with a face-centered cubic structure has not yet been synthesized. The reason is that, on the one hand, osmium and platinum are immiscible solid solutions and cannot be synthesized by traditional high-temperature quenching methods; on the other hand, it is still very difficult to eliminate the difference in reduction rates of different elements in the synthesis to achieve phase control.

[0045] To achieve single-phase synthesis of immiscible osmium-platinum solid solution nanoparticles in the presence of a support, overcome the current problem of catalytic performance degradation caused by uneven nanoparticle loading and achieve efficient hydrogen evolution reaction activity, this paper develops a method for synthesizing an in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0046] In order to make the objects, advantages and features of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and specific examples. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0047] Example 1

[0048] Step 1: 9.2 mg of potassium hexachloroosmate and 93.2 mg of chloroplatinic acid hexahydrate were dissolved in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounted for 10% of the total metal molar amount.

[0049] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 230°C.

[0050] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0051] Step 4: Wash the mixed solution three times with ethyl acetate, and then centrifuge and dry to obtain 114.942 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst.

[0052] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.1 Pt 0.9 / C, where Fcc indicates that the catalyst has a face-centered cubic structure and C indicates that the support is a carbon support. The present invention solves the technical problem of the difficulty in synthesizing osmium-platinum solid solutions and provides a new method for synthesizing atomically miscible osmium-platinum alloy particle catalysts.

[0053] Example 2

[0054] Step 1: Dissolve 26.5 mg of potassium hexachloroosmate and 72.5 mg of chloroplatinic acid hexahydrate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0055] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 230°C.

[0056] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0057] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 114.88 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0058] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0059] Example 3

[0060] Step 1: Dissolve 44.2 mg of potassium hexachloroosmate and 51.7 mg of chloroplatinic acid hexahydrate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 50% of the total metal molar amount.

[0061] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, degassed with liquid nitrogen three times, and then heated to 230°C.

[0062] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0063] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 114.05 mg of in-situ carbon-supported osmium platinum single-phase solid solution nanoalloy catalyst.

[0064] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.5 Pt 0.5 / C.

[0065] Example 4

[0066] Step 1: 61.9 mg of potassium hexachloroosmate and 31.1 mg of chloroplatinic acid hexahydrate were dissolved in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounted for 70% of the total metal molar amount.

[0067] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 230°C.

[0068] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0069] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 113.29 mg of in-situ carbon-supported osmium platinum single-phase solid solution nanoalloy catalyst.

[0070] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.7 Pt 0.3 / C.

[0071] Example 5

[0072] Step 1: Dissolve 26.4 mg of ammonium chloroosmate and 68.0 mg of potassium chloroplatinate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0073] Step 2: 387.2 mg of the mesoporous carbon support was dissolved in 1100 mL of diethylene glycol solvent, and the solution was degassed with liquid nitrogen three times to obtain a support solution, which was then heated to 280°C.

[0074] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0075] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 425.92 mg of in-situ carbon-supported osmium platinum single-phase solid solution nanoalloy catalyst.

[0076] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0077] Example 6

[0078] Step 1: Dissolve 26.4 mg of ammonium chloroosmate and 68.0 mg of potassium chloroplatinate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0079] Step 2: 774.7 mg of the mesoporous carbon support was dissolved in 1500 mL of diethylene glycol solvent, and the solution was degassed with liquid nitrogen three times to obtain a support solution, which was then heated to 280°C.

[0080] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0081] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 813.42 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0082] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0083] Example 7

[0084] Step 1: Dissolve 26.9 mg of sodium hexachloroosmate dihydrate and 78.7 mg of sodium hexachloroplatinate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0085] Step 2: 193.6 mg of carbon aerogel was dissolved in 550 mL of diethylene glycol solvent and degassed with liquid nitrogen three times to obtain a carrier solution, which was then heated to 180°C.

[0086] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0087] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 232.34 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0088] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0089] Example 8

[0090] Step 1: Dissolve 26.9 mg of sodium hexachloroosmate dihydrate and 78.7 mg of sodium hexachloroplatinate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0091] Step 2: 1936.0 mg of carbon aerogel carrier was dissolved in 1000 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 180°C.

[0092] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0093] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 1974.72 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0094] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0095] Example 9

[0096] Step 1: Dissolve 26.5 mg of potassium hexachloroosmate and 72.5 mg of chloroplatinic acid hexahydrate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0097] Step 2: 154.2 mg of acetylene black carrier was dissolved in 300 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 220°C.

[0098] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0099] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 190.39 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0100] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0101] Example 10

[0102] Step 1: Dissolve 26.5 mg of potassium hexachloroosmate and 72.5 mg of chloroplatinic acid hexahydrate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounts for 30% of the total metal molar amount.

[0103] Step 2: 693.9 mg of acetylene black carrier was dissolved in 1000 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 200°C.

[0104] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0105] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 730.09 mg of in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst.

[0106] In this embodiment, the chemical formula of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst is Fcc-Os 0.3 Pt 0.7 / C.

[0107] Comparative Example 1

[0108] Step 1: 88.5 mg of potassium hexachloroosmate was dissolved in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the osmium element accounted for 100% of the total metal molar amount.

[0109] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 230°C.

[0110] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0111] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 112.09 mg of carbon-supported osmium nanometal catalyst (Os / C).

[0112] Comparative Example 2

[0113] Step 1: Dissolve 103.6 mg of chloroplatinic acid hexahydrate in 5 mL of diethylene glycol solvent to prepare a uniformly mixed precursor solution in which the platinum element accounts for 100% of the total metal molar amount.

[0114] Step 2: 77.1 mg of acetylene black carrier was dissolved in 110 mL of diethylene glycol solvent, and the carrier solution was obtained after degassing with liquid nitrogen three times, and then heated to 230°C.

[0115] Step 3: In a nitrogen atmosphere, add the precursor solution dropwise to the heated carrier solution within 2 minutes, stir evenly, and keep warm at 230° C. for 5 minutes to obtain a mixed solution.

[0116] Step 4: The mixed solution was washed three times with ethyl acetate, and then centrifuged and dried to obtain 116.12 mg of carbon-supported platinum nanometal catalyst (Pt / C).

[0117] The in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalysts (hereinafter referred to as "osmium-platinum solid solution alloys") obtained in Examples 1, 2, 3, and 4, as well as the carbon-supported osmium nanometal catalyst obtained in Comparative Example 1 and the carbon-supported platinum nanometal catalyst obtained in Comparative Example 2 were subjected to XRPD (X-ray powder diffraction) detection. Figure 1 The radiation wavelength of each catalyst at 298K is The XRPD pattern shows that the osmium platinum solid solution alloys obtained in Examples 1, 2, 3, and 4 mainly exhibit a face-centered cubic crystal structure, and with the increase of the osmium element content, the {220} peak moves to a higher angle, which indicates that a solid solution alloy has been formed.

[0118] Next, the osmium platinum solid solution alloy obtained in Example 2, namely Fcc-Os 0.3 Pt 0.7The XRPD pattern (black dot area) and calculated pattern (red line) of / C were subjected to Rietveld refinement (Rietvel structure refinement) at 303K. The results are shown in Figure 2 As shown, there is basically no difference between the two results. 0.3 Pt 0.7 / C, its face-centered cubic lattice constant A is determined to be 3.913, which is smaller than platinum (A1=3.923) and larger than osmium (A2=3.868).

[0119] Furthermore, the XRPD patterns of the catalysts obtained in Examples 1, 2, 3, 4 and Comparative Examples 1 and 2 were subjected to Rietvel structure refinement, as shown in FIG. Figure 3 As shown, the obtained Fcc-Os x Pt 1-x The Pt ratios obtained by XRF (X-ray fluorescence spectroscopy) and EDX measurements showed a linear relationship, which was consistent with Vegard's law, which once again proved the formation of osmium-platinum solid solution alloy.

[0120] The loading state of the osmium-platinum solid solution alloys obtained in Examples 1, 2, 3, and 4 and the mixing state of osmium and platinum elements were evaluated by mapping measurements using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and STEM-energy dispersive X-ray (STEM-EDX). Figure 4 As shown, the Fcc-Os obtained in Example 2 0.3 Pt 0.7 / C as an example, where Figure a is the original HAADF-STEM image, which shows the single dispersion of osmium platinum solid solution alloy particles on the acetylene black support. In addition, other ratios of Fcc-Os x Pt 1-x / C also shows similar results, and according to the corresponding HAADF image, Fcc-Os x Pt 1-x The average diameters of / C particles (x=0.1, 0.3, 0.5, 0.7) were 5.1±0.6 nm, 5.3±0.8 nm, 3.2±0.5 nm, 2.6±0.3 nm, 3.7±0.5 nm, and 1.5±0.2 nm, respectively.

[0121] Figure 4 Figure b is Fcc-Os 0.3 Pt 0.7 STEM-energy dispersive X-ray distribution of osmium in / C;

[0122] Figure c is Fcc-Os 0.3 Pt 0.7STEM-energy dispersive X-ray distribution diagram of platinum element in / C; d is

[0123] Os 0.3 Pt 0.7 STEM-EDX overlay of the distribution of osmium and platinum in Fcc-Os 0.3 Pt 0.7 The uniform distribution of osmium and platinum in Fcc-Os / C provides direct evidence. x Pt 1-x The similar results of Fcc-Os / C demonstrated the formation of a uniform Fcc-Os x Pt 1-x / C solid solution.

[0124] In addition, Os x Pt 1-x The Os / Pt ratio of Fcc-Os / C can also be calculated from the EDX pattern, and the results are consistent with those evaluated by XRF measurement and XRPD Rietvel structure refinement, as shown in Table 1. Table 1 shows the Os / Pt ratio of Fcc-Os / C calculated by EDX pattern, XRF measurement, and XRPD Rietvel structure refinement. x Pt 1-x / Comparison table of Os / Pt ratios in C with preset ratios.

[0125] Table 1 Calculated Fcc-Os x Pt 1-x Comparison table of Os / Pt ratio in / C and preset ratio

[0126]

[0127] In Table 1, Samples represents the catalyst samples, Nominal ratio of Os / Pt represents the ratio of osmium to platinum weighed in each example, EDX ratio of Os / Pt represents the ratio of the two elements fed back by the EDX spectrum, XRFratio of Os / Pt represents the ratio of the two elements at the XRF measurement, and XRPD refinement ratio of Os / Pt represents the ratio of the two elements calculated by XRPD Rietvel structure refinement.

[0128] Furthermore, the metal loading on the carbon support and the catalyst loading on the working electrode in the catalysts obtained in Examples 1, 2, 3, 4 and Comparative Examples 1 and 2 were determined by XRF measurement. The results are shown in Table 2:

[0129] Table 2 Comparison of metal loading on carbon support and catalyst loading on working electrode

[0130] Catalyst type Metal loading Catalyst loading Pt / C 9.61％ <![CDATA[34.3μg metal ·cm -2 ]]> <![CDATA[Fcc-Os 0.1 Pt 0.9 / C]]> 10.15％ <![CDATA[36.3μg metal ·cm -2 ]]> <![CDATA[Fcc-Os 0.3 Pt 0.7 / C]]> 6.87％ <![CDATA[24.5μg metal ·cm -2 ]]> <![CDATA[Fcc-Os 0.5 Pt 0.5 / C]]> 8.69％ <![CDATA[31.0μg metal ·cm -2 ]]> <![CDATA[Fcc-Os 0.7 Pt 0.3 / C]]> 8.56％ <![CDATA[30.6μg metal ·cm -2 ]]> Os / C 7.62％ <![CDATA[27.2μg metal ·cm -2 ]]>

[0131] As shown in Table 2, Fcc-Os x Pt 1-x / C can be uniformly loaded on each glassy carbon electrode, and the average loading amount is slightly lower than that of platinum-based catalysts. At this loading amount, its catalytic activity is still good, so it can be used as a substitute for platinum-based catalysts.

[0132] Test Example 1

[0133] In this experiment, a three-electrode system was used to study the face-centered cubic Fcc-Os x Pt 1-x / C in 0.5M (mol / L) H2SO4 in the catalytic activity of alkaline hydrogen evolution reaction, the results are as follows Figure 5 shown. Figure 5 As shown in Figures a and b, Fcc-Os 0.3 Pt 0.7 η of / C 10 (10mA·cm -2 The overpotential is only 1.0mV, which is much better than that of platinum-based catalysts. As shown in Figure c, Fcc-Os 0.3 Pt 0.7 / C showed the highest mass activity at both 10 mV and 20 mV overpotentials, which were 1630 A·g metal -1 and 4192A·g metal -1 , is Pt / C(707A·g metal -1 and 1814A·g metal -1 ), which is more than twice that of most platinum-based catalysts, and the normalized surface mass activity is still the highest, at 6961 A·g surface -1 and 17900A·g surface -1 , surpassing the platinum catalyst, thus demonstrating its state-of-the-art intrinsic hydrogen evolution reaction activity. As shown in Figure d, Fcc-Os 0.3 Pt 0.7 Pt / C also shows a much lower Tafel slope than Pt / C, which confirms that its reaction kinetics is much faster.

[0134] In addition, the Fcc-Os 0.3 Pt 0.7 / C, commercial Pt / C and Pt / C, the hydrogen evolution reaction activity between Fcc-Os 0.3 Pt 0.7 / C loading on the electrode, η 10 The comparison results with other Pt-based catalysts are shown in Table 3.

[0135] Table 3 Fcc-Os 0.3 Pt 0.7 / C loading on the electrode, η 10 Comparison table with other Pt-based catalysts

[0136] Catalyst type Load <![CDATA[η 10 (mV)]]> <![CDATA[Fcc-Os 0.3 Pt 0.7 / C]]> Ca.2.5μgmetal 1.0 PtNiNPs / AuSA-NDC 50 μg 19.1 Pt@PtIr 16 μg 22 Pt / PtO2 / TiO2 Ca.100 μg 12 PtW / C 4 μg Pt 19.4 Fct-FePt 45.5 μg Pt 15.8 PtRu@RFCS 25 μg 19.7 Pd@PtCu / C Ca.7.3μgPt 19

[0137] Table 3 further confirms that Fcc-Os 0.3 Pt 0.7 / C has excellent hydrogen evolution reaction activity.

[0138] Test Example 2

[0139] In this experiment, a three-electrode system was used to study the face-centered cubic Fcc-Os x Pt 1-x / C catalytic activity in alkaline hydrogen evolution reaction in 1M (mol / L) KOH, the results are as follows Figure 6 As shown in Figures a and b, all Fcc-Os x Pt 1-x η of the C / C catalyst under alkaline conditions 10 and η 20 All of them are lower than commercial Pt / C, Pt / C prepared by polyol method and Pt / C prepared by NaBH4 method. 0.3 Pt 0.7 / C has a 171A·g at 10mV and 20mV overpotentials, respectively. metal - 1 and 338A·g metal - 1 The highest mass activity of Fcc-Os is shown in Figure c. After normalizing the surface atomic ratio, 0.3 Pt 0.7 / C still showed the highest surface mass activity at 20 mV overpotential, which was 1444 A·g surface - 1 , almost Pt / C(791A·g surface -1 As shown in Figure d, Fcc-Os x Pt 1-x The Tafel slope of Fcc-Os is lower than that of Pt / C, which again confirms that the reaction kinetics is much faster. x Pt 1-x / C has higher hydrogen evolution reaction activity.

[0140] In addition, Fcc-Os0.3 Pt 0.7 The ECSA (electrochemically active area) of Fcc-Os / C and Pt / C are very close, indicating that 0.3 Pt 0.7 / C has higher specific surface area activity. 0.3 Pt 0.7 The Rct (charge transfer resistance) of Fcc-Os / C (21.6Ω) is much smaller than that of Pt / C (63.2Ω), which further confirms that 0.3 Pt 0.7 / C has higher activity.

[0141] In summary, most face-centered cubic osmium platinum solid solution alloy catalysts show better catalytic activity for hydrogen evolution reaction (HER) than pure Pt / C under both acidic and alkaline conditions. 0.3 Pt 0.7 / C in 0.5M H2SO4 10 It is only 1.0mV, which is a top-level hydrogen evolution reaction catalyst.

[0142] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art will appreciate that modifications may be made to the technical solutions described in the above embodiments, or that some or all of the technical features therein may be replaced with equivalents; such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the present invention.

Claims

1. A method for synthesizing an in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst, characterized in that: The following steps are involved: Step 1: Weigh an osmium compound and a platinum compound separately, mix the two, and add them to a polyol solvent until they are completely dissolved to obtain a precursor solution; the molar ratio of the osmium compound to the platinum compound is 10-70:30-90, and the total molar amount of the osmium element and the platinum element in the precursor solution is 0.2 mmol; Step 2: preparing a carbon support and adding it to a polyol solvent until it is completely dissolved to obtain a support solution, and then heating the support solution to 150-300° C.; the mass of the carbon support is 2-99 times the total mass of the osmium element and the platinum element; Step 3: Under an inert atmosphere, add the precursor solution to the heated carrier solution within two minutes, stir evenly, and then heat and react to obtain a mixed solution; Step 4: Wash, centrifuge and dry the mixed solution in sequence to obtain an in-situ carbon-supported osmium-platinum solid solution nano-alloy catalyst.

2. The method for synthesizing the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 1, the osmium compound is selected from one or more of potassium hexachloroosmate, osmium (III) chloride hydrate, ammonium chloroosmate, sodium hexachloroosmium (IV) dihydrate, triosmium dodecacarbonyl, bis(cyclopentadienyl)osmium, and potassium osmate dihydrate; The platinum compound is selected from one or more of potassium chloroplatinate, chloroplatinic acid hexahydrate, platinum tetrachloride, sodium chloroplatinite, sodium hexachloroplatinate, tetrachloroplatinum, tetraammineplatinate, cisplatin, ammonium chloroplatinate, potassium chloroplatinite, tetraammineplatinum nitrate, potassium tetranitroplatinate (II), potassium trichloroammineplatinate (II), and tetraammineplatinum chloride hydrate.

3. The method for synthesizing the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 2, the carbon support is dissolved in a polyol solvent and then degassed three times using liquid nitrogen to obtain a support solution.

4. The method for synthesizing the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 2, the carbon carrier is selected from one of acetylene black carrier, carbon nanotube carrier, mesoporous carbon carrier, and carbon aerogel carrier.

5. The method for synthesizing the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 2, the carrier solution is heated to 230°C.

6. The method for synthesizing the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 1 and step 2, the polyol solvent is any one of diethylene glycol, methanol, ethanol, n-propanol, isopropanol, n-butanol, pentanol, hexanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butylene glycol, dibutylene glycol, tributylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, butylene glycol monomethyl ether, butylene glycol monoethyl ether, glycerol, diglycerol, polyglycerol, trimethylolpropane, pentaerythritol or oleylamine.

7. The method for synthesizing the in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst according to claim 1, characterized in that: In step 3, the heat preservation reaction time is 5 minutes.

8. An in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst, characterized by: The catalyst is prepared by the synthesis method of the in-situ carbon-supported osmium platinum single-phase solid solution nano-alloy catalyst according to any one of claims 1 to 7, and its chemical formula is Fcc-Os x Pt 1-x / C, wherein 0<x<1, Fcc represents a face-centered cubic structure, and C represents a carbon support.

9. The in-situ carbon-supported osmium-platinum single-phase solid solution nanoalloy catalyst according to claim 8, characterized in that: The chemical formula is Fcc-Os 0.3 Pt 0.7 / C.

10. Use of the in-situ carbon-supported osmium-platinum single-phase solid solution nano-alloy catalyst according to claim 8 or 9 in electrocatalysis of hydrogen evolution reaction.

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