Porous Pt-CuOx catalyst with high hydrogen evolution activity and preparation method and application thereof

Abstract

The invention discloses a porous Pt-CuOx catalyst with high hydrogen evolution activity as well as a preparation method and application of the porous Pt-CuOx catalyst. The porous Pt-CuOx catalyst provided by the invention has micro-nano hierarchical pores and an antenna-shaped surface structure. The preparation method comprises the following steps: uniformly mixing copper powder and aluminum powder in proportion, carrying out compression molding on the mixed powder, sintering the powder to obtain a CuAl intermetallic compound, putting a sintered product into a NaOH solution, corroding to obtain micro-nano porous CuOx, uniformly stirring dry powder and PVP (Polyvinyl Pyrrolidone) in the solution, centrifuging to remove supernate, adding a platinum metal salt solution, stirring, evaporating and drying to obtain the Pt-CuOx material. According to the Pt-CuOx catalyst, Pt nanoclusters are loaded through a two-step dealloying-impregnation method, a micro-nano-scale hierarchical pore structure is constructed, the surface is distributed in an antenna shape, the low hydrogen evolution overpotential of 150 mV and the low Tafel slope of 125 mV dec-1 are shown in the hydrogen evolution reaction, the overpotential is improved by 80 mV compared with the overpotential of an unloaded Cu-based material, and the accessibility of active sites is improved through the special surface structure.

Description

Technical Field

[0001] The present invention relates to the field of metal catalysts, and in particular to a porous Pt-CuO catalyst with high hydrogen evolution activity. x Catalyst and its preparation method and application. Background Art

[0002] Hydrogen energy is considered to be one of the most promising clean energy sources to replace traditional fossil energy due to its high energy density, abundant sources and pollution-free combustion products. The main methods for preparing hydrogen include water electrolysis and fossil fuel reforming. Among them, the electrocatalytic hydrogen evolution reaction (HER) is a key step in the electrochemical decomposition of water and plays a vital role in the production and utilization of hydrogen energy. In order to improve the efficiency of the hydrogen evolution reaction, the selection of electrocatalysts is crucial. The surface structure (pore structure and surface morphology, etc.) of the electrocatalyst substrate / matrix has an important influence on the transport of substances such as water and hydrogen during the hydrogen evolution reaction.

[0003] Compared with dense oxides, porous metal oxides have the characteristics of high specific surface area and large pore size, and some also have special morphology and structural characteristics. These characteristics enable porous metal oxides to provide more active sites in catalytic reactions, which are conducive to the diffusion, adsorption and activation of reactant molecules, thereby enhancing catalytic efficiency. However, the surface structure of porous metal oxides prepared by traditional methods is relatively simple (CN116422335A), and CN107398554A discloses a method for preparing metallic copper by a dealloying method, but the dealloying precursor has a single phase distribution, and the dealloying product does not present a hierarchical pore structure and the surface does not grow a nanoscale microstructure. In practical applications, its catalytic activity may still be low, and it is necessary to further solve the problem of its single surface structure / pore structure by optimizing the preparation scheme.

[0004] Another important parameter affecting electrocatalytic performance is the exposure and / or dispersion of active sites. x ) is a low-cost, environmentally friendly material and has been widely studied as a candidate support material in electrocatalytic reactions in recent years. x The unique structure and good electrocatalytic properties of CuO make it a potential in hydrogen evolution reaction. x Generally, the catalytic activity is low and the stability is poor. On the other hand, noble metal catalysts (mainly Pt) are also widely used in hydrogen evolution reaction due to their excellent catalytic performance, but the limited resources and high prices of noble metals restrict their large-scale application. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for preparing a Pt-CuOx catalyst with high hydrogen evolution activity, so as to solve the problems of single surface structure of dealloyed products and low catalytic rate of copper-based oxides in HER reaction.

[0006] The second object of the present invention is to provide a Pt-CuOx catalyst with high hydrogen evolution activity prepared by the above preparation method, which has high catalytic activity.

[0007] The third object of the present invention is to provide the application of the above-mentioned Pt-CuOx catalyst with high hydrogen evolution activity.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] In the first aspect, the present invention provides a method for preparing a Pt-CuOx catalyst with high hydrogen evolution activity, which adopts a two-step self-exothermic / dealloying-impregnation method to prepare the required catalyst. First, a CuOx having a porous structure is prepared by a self-exothermic / dealloying method. x The substrate is then impregnated with CuO x Nanoclusters of Pt grow on the substrate, eventually forming antenna-like micro-nanoporous Pt-CuO x The specific steps include:

[0010] Step 1: Evenly mix Cu powder and Al powder according to the copper-aluminum atomic ratio of 17:83, and press the mixed powder to obtain a green body; sinter the green body in an argon atmosphere to obtain a sintered product CuAl intermetallic compound;

[0011] Step 2: Place the sintered product prepared in step 1 into a 10wt.% to 30wt.% NaOH solution and perform chemical dealloying at 30 to 50°C until bubbles are no longer generated, followed by drying. The dried product is micro-nano porous CuO x Powder; the mass ratio of the sintered product to the volume of the NaOH solution is 60 mg: 10 mL to 30 mL;

[0012] Step 3: Prepare the CuO x The powder and PVP are placed in high-purity water and stirred evenly, and the supernatant is removed after centrifugation to obtain a centrifugal precipitate;

[0013] Step 4: Prepare a 0.025 mol / L platinum metal salt solution, add it to the centrifugal precipitate obtained in step 3, stir and evaporate the mixed solution in a water bath, and the dried product is porous Pt-CuO x Material.

[0014] The present invention firstly uses copper powder and aluminum powder as original powder, uniformly mixes and cold presses them into discs by tablet pressing mold, and sinters them in argon atmosphere to generate self-exothermic reaction; chemically dealloys the sintered blank in NaOH alkaline solution until bubbles disappear; vacuum drying product is porous CuO x ; CuO x The powder was ultrasonically immersed in high-purity water, PVP was added and stirred, and the mixture was thoroughly mixed; the supernatant was removed by centrifugation, and a platinum metal salt solution was added, stirred at a certain temperature, evaporated and dried, and finally the tentacle-shaped micro-nano porous Pt-CuO was obtained. x Material.

[0015] Preferably, in step 1, the particle size of the Cu powder is 35-45 μm, and the particle size of the Al powder is 38-74 μm; the sintering temperature is 600° C., followed by immediate cooling.

[0016] Preferably, the drying process in step 2 is: vacuum drying at 60-80° C. for 10-24 hours.

[0017] Preferably, the CuO in step 3 x The mass ratio of powder to PVP is 3:2; the CuO x The volume ratio of powder mass to high-purity water is 60 mg: 5-50 mL; the stirring time is 1-2 h, and the stirring speed is 300-400 rpm.

[0018] Preferably, the centrifugation process in step three is: rotation speed 4500-5500 rpm, time 1-10 min.

[0019] Preferably, the platinum metal salt in step 4 is selected from any one of acetylacetonate platinum, chloroplatinic acid, potassium chloroplatinate, ammonium chloroplatinate and tetraammineplatinum dichloride, and the volume of the platinum metal salt solution added is 300 μL to 2000 μL.

[0020] Preferably, the water bath heating temperature in step 4 is 60-100° C., and the stirring is performed at a magnetic stirring speed of 300-400 rpm for 2-4 hours.

[0021] In a second aspect, the present invention provides a Pt-CuO with high hydrogen evolution activity prepared by the above preparation method. x catalyst.

[0022] The Pt-CuO x The catalyst has a complex tentacle-like hierarchical porous structure, with micropore sizes ranging from 10 to 30 μm and nanopore sizes ranging from 35 to 75 nm.

[0023] The Pt-CuO x The Pt loading form in the catalyst is nano clusters, and the actual Pt loading amount is 0.94-1.3wt.%.

[0024] In a third aspect, the present invention also provides the above-mentioned Pt-CuO with high hydrogen evolution activity. x Application of catalysts in HER reaction of water electrolysis.

[0025] The Pt-CuO x The catalyst has high hydrogen evolution activity at 10 mA cm -2 The lower hydrogen evolution overpotential is 150 mV and the lower Tafel slope is 125 mV dec -1 The Pt-CuO x The catalyst overpotential is increased by 80 mV compared with the unsupported copper-based catalyst.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention adopts direct pressing and sintering of Cu and Al powders without the need for a heat preservation process, and stably obtains the intersecting Al phase and CuAl2 phase through the eutectic reaction, with stable phases and fast sintering; further treatment is performed by dealloying to overcome the problems of low porosity of the sintered blank at the Cu and Al eutectic components and irregular shape of the sintered blank during the endothermic and exothermic processes, and prepares a micro-nano porous structure and a micro-nano bicontinuous ligament structure; further treatment is performed by combining an impregnation method to improve the singleness of the surface structure on the basis of the hierarchical porous structure, and the oxide ratio, surface micromorphology and Pt existence form are adjusted by changing the loading amount to prepare a porous Pt-CuO with a surface nano-tentacle-level distribution. x Material.

[0028] 2. This invention combines the self-exothermic / dealloying method with the impregnation method for the first time, accurately controls the Pt loading amount, and prepares the surface antenna-like micro-nano porous Pt-CuO loaded with Pt nanoclusters. x The catalyst makes the catalyst composition and structure more refined and controllable, enhances the conductivity and catalytic performance of the catalyst in HER, and has a much higher activity than unloaded copper-based catalysts. x The catalyst can also be used as anode material for secondary batteries and photocatalyst, thanks to the hierarchical porous structure, which is conducive to exposing more reaction sites and improving the storage efficiency and kinetic performance of secondary batteries.

[0029] 3. The present invention uses trace amounts of Pt and CuO x The composite and porous structure design can reduce the amount of Pt to a certain extent, thereby reducing the cost of the catalyst. The preparation process is relatively simple and controllable, which is conducive to the large-scale production and application of the catalyst, and produces less environmental pollution, which meets the requirements of green chemistry and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The Pt-CuO x Material preparation roadmap.

[0031] Figure 2 CuO at different dealloying temperatures in the present invention x SEM images of materials: (a) 10℃, (b) 40℃, (c) 80℃.

[0032] Figure 3 CuO under different etching solution concentrations of the present invention x Material SEM images: (a) 10wt.%, (b) 20wt.%, (c) 30wt.%.

[0033] Figure 4 Pt-CuO in Example 3 of the present invention x Material SEM images: (ac) 0.94wt.%Pt-CuO x : (a) 100 times, (b) 30 times, (c) 10 times; (df) 1.20wt.%Pt-CuO x : (d) 100 times, (e) 30 times, (f) 10 times; (gi) 1.30wt.%Pt-CuO x :(g) 100 times, (h) 30 times, (i) 10 times.

[0034] Figure 5 Pt-CuO in Example 3 of the present invention x TEM images of materials: (a) 100nm, (b) 50nm, (c) 10nm, (d) 5nm.

[0035] Figure 6 CuO in Example 3 of the present invention x With Pt-CuO x WAXS image of the material.

[0036] Figure 7 CuO in Example 3 of the present invention x With Pt-CuO x Material hydrogen evolution performance diagram: (a) is LSV diagram, (b) is Tafel curve diagram, (c) is double layer capacitance C dl picture. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example 1

[0039] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0040] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product Cu-Al intermetallic compound.

[0041] Step 2: Prepare a 10wt.% NaOH alkaline solution, place it in a 10°C oven, put 60mg of the sintered product in step 1 into 5mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 60°C for 5h. The dried product is micro-nano porous CuO x powder.

[0042] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 5 mL of high-purity water and stirred for 1 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 1 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0043] Step 4: Add 300 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, and stir the mixed solution at 300 rpm in a 60°C water bath for about 2 h until the solution is completely dry. The resulting product is porous 0.94 wt.% Pt-CuO x Materials, collect the materials and grind them thoroughly for later use.

[0044] Embodiment 2:

[0045] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0046] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product CuAl intermetallic compound.

[0047] Step 2: Prepare a 10wt.% NaOH alkaline solution, place it in a 10°C oven, put 60mg of the sintered product in step 1 into 12mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 60°C for 10h. The dried product is micro-nano porous CuO x powder.

[0048] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 10 mL of high-purity water and stirred for 1 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 5 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0049] Step 4: Add 300 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, and stir the mixed solution at 300 rpm in a 70°C water bath for about 3 h until the solution is completely dry. The resulting product is porous 1.30 wt.% Pt-CuO x Materials, collect the materials and grind them thoroughly for later use.

[0050] Embodiment 3:

[0051] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0052] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product CuAl intermetallic compound.

[0053] Step 2: Prepare a 20wt.% NaOH alkaline solution, place it in a 40°C oven, put 60mg of the sintered product in step 1 into 20mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 60°C for 12h. The dried product is micro-nano porous CuO x powder.

[0054] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 20 mL of high-purity water and stirred for 1 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 5 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0055] Step 4: Add 1000 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, and stir the mixed solution at 300 rpm in a water bath at 80°C for about 4 h until the solution is completely dry. The resulting product is porous 1.20 wt.% Pt-CuO x Materials, collect the materials and grind them thoroughly for later use.

[0056] Embodiment 4:

[0057] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0058] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product CuAl intermetallic compound.

[0059] Step 2: Prepare a 30wt.% NaOH alkaline solution, place it in an 80°C oven, put 60mg of the sintered product in step 1 into 30mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 70°C for 15h. The dried product is micro-nano porous CuO x powder.

[0060] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 30 mL of high-purity water and stirred for 1 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 10 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0061] Step 4: Add 2000 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, stir the mixed solution at 300 rpm in a 90°C water bath for about 5 hours until the solution is completely dry, collect the material and grind it thoroughly for later use.

[0062] Embodiment 5:

[0063] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0064] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product CuAl intermetallic compound.

[0065] Step 2: Prepare a 20wt.% NaOH alkaline solution, place it in a 40°C oven, put 60mg of the sintered product in step 1 into 20mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 80°C for 20h. The dried product is micro-nano porous CuO x powder.

[0066] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 40 mL of high-purity water and stirred for 1 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 10 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0067] Step 4: Add 2000 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, stir the mixed solution at 300 rpm in a 100°C water bath for about 3 hours until the solution is completely dry, collect the material and grind it thoroughly for later use.

[0068] Embodiment 6:

[0069] This embodiment provides a method for preparing a porous Pt-CuOx catalyst with high hydrogen evolution activity. Figure 1 As shown, the following steps are included:

[0070] Step 1: Evenly mix Cu powder with a particle size of 35 to 45 μm and Al powder with a particle size of 38 to 74 μm according to a copper-aluminum atomic ratio of 17:83, press the mixed powder to obtain a disc-shaped green body, heat the disc-shaped green body to 600° C. in an argon atmosphere for sintering, and then immediately cool it to obtain a sintered product CuAl intermetallic compound.

[0071] Step 2: Prepare a 20wt.% NaOH alkaline solution, place it in a 40°C oven, put 60mg of the sintered product in step 1 into 20mL of the alkaline solution for corrosion until bubbles no longer occur, and then vacuum dry it at 80°C for 24h. The dried product is micro-nano porous CuO x powder.

[0072] Step 3: Prepare CuO from step 2 x 60 mg of powder and 40 mg of PVP were placed in 50 mL of high-purity water and stirred for 2 h to achieve uniform distribution. The solution was centrifuged at 5000 rpm for 20 min, the supernatant was removed, and the centrifugal precipitate was collected for later use.

[0073] Step 4: Add 2000 μL of 0.025 mol / L H2PtCl6 solution to the centrifugal precipitate in step 3, stir the mixed solution at 300 rpm in a 90°C water bath for about 1 hour until the solution is completely dry, collect the material and grind it thoroughly for later use.

[0074] Example 3 is the optimal experimental condition.

[0075] like Figure 2 As shown, the product CuO under different etching solution concentrations is shown. x Appearance. Figure 2 As shown in (a), when the concentration of the etching solution is 10wt.%, the corrosion rate is low, the corrosion is not complete, and the structure is incomplete; Figure 2 As shown in (b), when the concentration of the corrosive solution is 20wt.%, the ligament size is uniform and the structural morphology is complete; Figure 2 As shown in (c), when the concentration of the corrosive solution is 30wt.%, the corrosion rate is fast, the ligaments are coarsened, and the reaction is violent, resulting in partial structural damage.

[0076] like Figure 3 As shown, the product CuO at different dealloying temperatures is shown. x Appearance. Figure 3 As shown in (a), when the corrosion temperature is 10°C, the temperature is low, the corrosion time is short, and there are impurities on the ligament surface that have not reacted completely; Figure 3 As shown in (b), when the corrosion temperature is 40°C, the ligament surface is flat and the structure is uniform; Figure 3 As shown in (c), when the corrosion temperature is 80℃, the temperature rises, the Al element dissolves and the Cu element rearranges rapidly, the ligament growth rate accelerates, and the ligament coarsening is serious.

[0077] like Figure 4 As shown, the effect of different Pt loadings on the product Pt-CuO x The influence of morphology. Figure 4 As shown in (ac), the Pt-CuO prepared by the present invention x When the material loading is 0.94wt.%, the lower loading is not conducive to the uniform growth of graded porous ligaments, and some cubic cuprous oxide is unevenly attached to the skeleton; Figure 4 As shown in (df), the Pt-CuO prepared by the present invention x When the Pt loading of the material is 1.20wt.%, it has a complex hierarchical porous structure with micropore size of 10-30μm and nanopore size of 35-75nm. The surface has abundant special tentacle-like structures. This provides the basic conditions for the rapid mass transfer of water / hydrogen and the uniform dispersion and exposure of Pt in HER. Figure 4 As shown in (gi), the Pt-CuO prepared by the present invention x When the material loading was 1.30 wt.%, excessive Pt loading increased the formation of irregular cubic / octahedral cuprous oxide, which adhered to the ligament surface and accumulated in the micro-nano pores.

[0078] In Example 3, Figure 5 As shown, the Pt-CuO prepared by the present invention x The material shows the following characteristics: It has obvious surface antenna-like micro-nanopore structure; the lattice fringes of the high-magnification TEM photo show that CuO xThe formation of nanoscale Pt clusters (about 2 nm in size) improves the utilization of Pt and is beneficial to improving HER activity.

[0079] In Example 3, Figure 6 As shown, the catalyst mainly comprises Cu, Cu2O, CuO and Pt. The Pt-CuO prepared by the present invention x The material shows obvious Pt characteristic peaks (compared to CuO without platinum loading by the second step impregnation method). x Materials), combined Figure 2 Medium and high magnification TEM images confirm that Pt-CuO x The presence of Pt nanoclusters in the material.

[0080] The Pt-CuO prepared in Example 3 x The material is tested for electrocatalytic hydrogen evolution performance. The main steps are as follows:

[0081] In the three-electrode system, a glassy carbon electrode is used as the working electrode, a Hg / HgO electrode is used as the reference electrode, and a platinum / carbon rod electrode is used as the counter electrode. The preparation process of the working electrode is to disperse 4 mg of the catalyst in 300 μL of isopropanol, 200 μL of high-purity water and 20 μL of 5wt.% Nafion and fully ultrasonicate to achieve uniform dispersion, then drop 5 μL of the catalyst slurry on the glassy carbon electrode and dry it naturally at room temperature. The electrolyte is 1M KOH solution. The LSV test potential range is 0.1-0.5V vs.RHE. Control example: pure CuO without Pt loading by impregnation method x catalyst.

[0082] like Figure 7 As shown, CuO x and Pt-CuO x The electrochemical properties of Figure 7 (a) Pt-CuO prepared by a two-step self-exothermic / dealloying-impregnation method x The catalyst showed excellent catalytic performance in HER electrocatalysis at 10 mA cm -2 The hydrogen evolution overpotential is 150mV, which is lower than that of CuO without platinum loading. x Increased by one third (150mV vs. 230mV); Figure 7 (b) Pt-CuO prepared by a two-step self-exothermic / dealloying-impregnation method x The catalyst has a lower Tafel slope (125mV dec -1 ), i.e., fast transport dynamics; e.g. Figure 7 (c) Pt-CuO prepared by a two-step self-exothermic / dealloying-impregnation method x The catalyst has a high double-layer capacitance.

[0083] In summary, the present invention successfully constructed a Pt-CuO with a complex surface structure through a two-step self-exothermic / dealloying-impregnation method. x Catalyst, this preparation method avoids the traditional CuO x The disadvantages of the base material surface structure is single and the porosity is insufficient. The operation is relatively simple, the reaction process is controllable, and large-scale production can be achieved. The catalyst prepared by the two-step method has a hierarchical micro-nano porous structure and a tentacle-like structure on the surface. On the one hand, it improves the transmission of gas and water; on the other hand, it is conducive to the loading and exposure of active sites, greatly improving the catalytic activity.

[0084] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. However, it should be pointed out that the electrocatalyst prepared by simply replacing the precursor Cu metal and / or the loading source Pt metal salt using the same similar two-step self-exothermic / dealloying-impregnation method, such as Pt-FeO x , Pt-CoO x , Pt-NiO x , Pt-ZnO x ;Ir-FeO x , Ir-CoO x , Ir-NiO x , Ir-CuO x , Ir-ZnO x ;Ru-FeO x , Ru-CoO x ,Ru-NiO x , Ru-CuO x , Ru-ZnO x ; Pd-FeO x , Pd-CoO x , Pd-NiO x , Pd-CuO x , Pd-ZnO x The above electrocatalysts are also used in the fields of electrolysis of water / electrochemical synthesis applications such as oxygen evolution reaction (OER) similar to hydrogen evolution, 5-hydroxymethylfurfural oxidation reaction (HMFOR), electrochemical NO reduction reaction (NORR), electrochemical reduction of nitrate (NO3RR), etc., which rely on porous matrices and precious metals to achieve material transport and catalytic activity, and the like, and should also belong to the protection scope of the present invention. Any modification, equivalent substitution and improvement made by any technician familiar with the technical field within the technical scope disclosed by the present invention, within the spirit and principle of the present invention, should be covered within the protection scope of the present invention.

Claims

1. A Pt-CuO with high hydrogen evolution activity x The method for preparing a catalyst is characterized in that: The following steps are involved: Step 1: Evenly mix Cu powder and Al powder according to the copper-aluminum atomic ratio of 17:83, and press the mixed powder to obtain a green body; sinter the green body in an argon atmosphere to obtain a sintered product CuAl intermetallic compound; Step 2: Place the sintered product prepared in step 1 into a 10wt.% to 30wt.% NaOH solution and perform chemical dealloying at 30 to 50°C until bubbles are no longer generated, followed by drying. The dried product is micro-nano porous CuO x Powder; the mass ratio of the sintered product to the volume of the NaOH solution is 60 mg: 10 mL to 30 mL; Step 3: Prepare the CuO x The powder and PVP are placed in high-purity water and stirred evenly, and the supernatant is removed after centrifugation to obtain a centrifugal precipitate; Step 4: Prepare a 0.025 mol / L platinum metal salt solution, add it to the centrifugal precipitate obtained in step 3, stir and evaporate the mixed solution in a water bath, and the dried product is porous Pt-CuO x Material.

2. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: In step 1, the particle size of the Cu powder is 35-45 μm, and the particle size of the Al powder is 38-74 μm; the sintering temperature is 600° C., and then the temperature is immediately lowered.

3. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: The drying process in step 2 is: vacuum drying at 60-80° C. for 10-24 hours.

4. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: CuO in step 3 x The mass ratio of powder to PVP is 3:2; the CuO x The volume ratio of powder mass to high-purity water is 60 mg: 5-50 mL; the stirring time is 1-2 h, and the stirring speed is 300-400 rpm.

5. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: The centrifugation process in step 3 is: rotation speed 4500-5500 rpm, time 1-10 min.

6. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: The platinum metal salt in step 4 is selected from any one of acetylacetonate platinum, chloroplatinic acid, potassium chloroplatinate, ammonium chloroplatinate and dichlorotetraammineplatinum, and the volume of the platinum metal salt solution added is 300 μL to 2000 μL.

7. A Pt-CuO with high hydrogen evolution activity according to claim 1 x The method for preparing a catalyst is characterized in that: In step 4, the water bath heating temperature is 60-100° C., and the stirring is carried out at a stirring speed of 300-400 rpm for 2-4 hours.

8. Pt-CuO with high hydrogen evolution activity obtained by the preparation method according to any one of claims 1 to 7 x catalyst.

9. Pt-CuO with high hydrogen evolution activity according to claim 8 x Application of catalysts in HER reaction of water electrolysis.

Images