Synergistic method of alkaline electrolytic water hydrogen evolution catalyst

Abstract

The invention provides a synergistic method of an alkaline water electrolysis hydrogen evolution catalyst, and belongs to the technical field of water electrolysis hydrogen production, the method comprises the following steps: S1, selecting or preparing a certain amount of a hydrogen evolution catalyst A; s2, taking a certain amount of transition metal hydride B, and compounding the transition metal hydride B with the hydrogen evolution catalyst A in the S1 to obtain a composite material C; and S3, performing electrochemical testing on the hydrogen evolution catalyst A, the transition metal hydride B and the composite material C to obtain an electrolyzed water cathodic polarization curve. According to the method, the catalyst and the transition metal hydride are compounded, the alkaline hydrogen evolution catalytic activity can be improved, the power consumption of hydrogen production through water electrolysis is reduced, and the synergistic technology has the advantages of being low in cost, remarkable in effect and high in universality and has important application value in the field of hydrogen production through alkaline water electrolysis.

Description

Technical Field

[0001] The invention belongs to the field of hydrogen production by water electrolysis, and relates to a method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst, specifically, the catalyst is compounded with a transition metal hydride that is stable under alkaline conditions to achieve a significant improvement in the hydrogen evolution catalytic activity. Background Art

[0002] Hydrogen energy has the characteristics of high calorific value, green environmental protection, and renewable, and is expected to replace traditional fossil energy. The earth has abundant reserves of hydrogen and mainly exists in the form of water, but there are very few hydrogen resources available for direct use. Hydrogen is mainly produced from fossil energy in industry. Electrolysis of water based on renewable electricity is a promising green hydrogen production technology. Among them, alkaline electrolyzers have attracted much attention due to their low cost, and their installed capacity has increased dramatically in recent years. However, the biggest pain point of alkaline electrolyzers is the high cost of electricity, which is determined by the electrochemical reaction mechanism under alkaline conditions. The proton concentration in the alkaline electrolyte is low, and the active hydrogen on the electrode surface mainly comes from the dissociation of water molecules (ie, Volmer reaction: *+H2O+e-=*H+OH - ). The kinetic hysteresis of this process produces a high overpotential, which leads to increased energy consumption and seriously restricts the economic benefits of hydrogen production by alkaline water electrolysis. Even for the best performing platinum catalyst, the hydrogen evolution kinetics under alkaline conditions are 2 to 3 orders of magnitude lower than those in acidic conditions. Therefore, reducing the water dissociation energy barrier to increase the Volmer reaction rate is the key to achieving efficient hydrogen production by alkaline water electrolysis.

[0003] In response to this problem, patent CN117926339A proposes a platinum-based composite catalyst for alkaline water electrolysis and its preparation method, a platinum nanoparticle catalyst supported by a transition metal-nitrogen-carbon matrix, in which the transition metal can promote water dissociation, thereby accelerating the hydrogen evolution reaction on the surface of the platinum catalyst. This method can enhance the alkaline hydrogen evolution catalytic activity of platinum, but the catalyst synthesis conditions are harsh and the preparation process is complicated, which poses certain challenges in large-scale production and application. Therefore, it is crucial to develop a technology that effectively improves the catalytic activity of alkaline hydrogen evolution, but there is still a lack of effective solutions. Summary of the invention

[0004] Based on the above analysis, the present invention discloses a technology for improving the catalytic activity of alkaline hydrogen evolution by using transition metal hydrides. Specifically, a hydrogen evolution catalyst is grown on the surface of a transition metal hydride that is stable under alkaline conditions or they are directly mixed to form a composite material. The lattice hydrogen in the transition metal hydride is used to increase the concentration of active hydrogen on the catalyst surface, thereby avoiding the problem of slow Volmer reaction rate and achieving the effect of significantly improving the catalytic activity of alkaline hydrogen evolution.

[0005] The present invention adopts the following technical solutions to solve the above problems:

[0006] A method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst, the method comprising the following steps:

[0007] S1: Select or prepare a certain amount of hydrogen evolution catalyst A;

[0008] S2: taking a certain amount of transition metal hydride B, and compounding it with the hydrogen evolution catalyst A in S1 to obtain a composite material C;

[0009] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0010] Furthermore, in S1, the hydrogen evolution catalyst A is a noble metal material or one or more of transition metal phosphides, sulfides, nitrides, borides, and the like.

[0011] Furthermore, in S2, the transition metal hydride B is one or more of titanium hydride, yttrium hydride, samarium hydride, palladium hydride, nickel hydride, etc., which are stable in the hydrogen evolution reaction under alkaline conditions.

[0012] Furthermore, in S2, the composite method of the hydrogen evolution catalyst A and the transition metal hydride B includes two methods, which include growing the hydrogen evolution catalyst A on the surface of the transition metal hydride B or directly mixing the hydrogen evolution catalyst A and the transition metal hydride B.

[0013] Furthermore, the mixing method of the hydrogen evolution catalyst A and the transition metal hydride B includes solution mixing, mechanical mixing or grinding mixing.

[0014] The present invention is based on the principle that transition metal hydrides can release active hydrogen atoms in the hydrogen evolution reaction, and combines them with hydrogen evolution catalysts to increase the concentration of active hydrogen atoms on the catalyst surface, thereby improving the alkaline hydrogen evolution catalytic activity, and has very high application value in the field of alkaline water electrolysis hydrogen production. Compared with the existing alkaline water electrolysis hydrogen evolution catalyst modification method, the synergistic technology provided by the present invention has the following characteristics:

[0015] (1) The effect is remarkable. In the hydrogen evolution reaction, the lattice hydrogen of the transition metal hydride can overflow and be replenished, which can increase the concentration of active hydrogen on the surrounding catalyst surface. The transition metal hydride can increase the concentration of active hydrogen atoms near the catalyst, effectively circumventing the problem of slow Volmer reaction rate, thereby achieving a significant improvement in the catalytic activity of alkaline hydrogen evolution.

[0016] (2) Low cost: using low-cost transition metal hydrides can significantly increase efficiency and significantly reduce the hydrogen evolution overpotential;

[0017] (3) Strong universality. The catalytic activity of various hydrogen evolution catalysts is significantly improved after being combined with transition metal hydrides;

[0018] (4) This technology combines the catalyst with transition metal hydride to enhance the catalytic activity of alkaline hydrogen evolution and reduce the power consumption of hydrogen production by water electrolysis. It has the characteristics of low cost, significant effect and strong universality, and has important application value in the field of hydrogen production by alkaline water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is the XRD pattern of titanium hydride-supported platinum nanoparticles prepared in Example 1;

[0021] Figure 2 TEM image of titanium hydride-supported platinum nanoparticles prepared in Example 1;

[0022] Figure 3 This is the cathode polarization curve of water electrolysis of titanium hydride-supported platinum nanoparticles prepared in Example 1;

[0023] Figure 4 This is a constant potential test curve of titanium hydride-supported platinum nanoparticles prepared in Example 1;

[0024] Figure 5 XRD pattern of titanium hydride supported molybdenum sulfide prepared in Example 2;

[0025] Figure 6 Cathodic polarization curve of electrolyzed water of titanium hydride supported molybdenum sulfide prepared in Example 2;

[0026] Figure 7 The cathode polarization curve of water electrolysis of the titanium hydride and nickel sulfide mixed catalyst prepared in Example 3;

[0027] Figure 8 The cathode polarization curve of water electrolysis of the mixed catalyst of yttrium hydride and nickel sulfide prepared in Example 4;

[0028] Fig. 9 This is the cathode polarization curve for water electrolysis of the mixed catalyst of yttrium hydride and cobalt sulfide prepared in Example 5. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] A method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst, the method comprising the following steps:

[0032] S1: Select or prepare a certain amount of hydrogen evolution catalyst A;

[0033] S2: taking a certain amount of transition metal hydride B, and compounding it with the hydrogen evolution catalyst A in S1 to obtain a composite material C;

[0034] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0035] Furthermore, in S1, the hydrogen evolution catalyst A is a noble metal material or one or more of transition metal phosphides, sulfides, nitrides, borides, and the like.

[0036] Furthermore, in S2, the transition metal hydride B is one or more of titanium hydride, yttrium hydride, samarium hydride, palladium hydride, nickel hydride, etc., which are stable in the hydrogen evolution reaction under alkaline conditions.

[0037] Furthermore, in S2, the composite method of the hydrogen evolution catalyst A and the transition metal hydride B includes two methods, which include growing the hydrogen evolution catalyst A on the surface of the transition metal hydride B or directly mixing the hydrogen evolution catalyst A and the transition metal hydride B.

[0038] Furthermore, the mixing method of the hydrogen evolution catalyst A and the transition metal hydride B includes solution mixing, mechanical mixing or grinding mixing.

[0039] Compared with the prior art, the present invention relies on the principle that transition metal hydrides can release active hydrogen atoms in the hydrogen evolution reaction, and combines them with hydrogen evolution catalysts to increase the concentration of active hydrogen atoms on the catalyst surface, thereby demonstrating beneficial effects in the hydrogen evolution reaction and achieving a significant increase in the catalytic activity of alkaline hydrogen evolution. The present invention has the advantages of significant effect, low cost, and strong universality, and has important application value in the field of hydrogen production by alkaline water electrolysis.

[0040] Example 1

[0041] In this embodiment, the hydrogen evolution catalyst A is platinum, and the transition metal hydride B is titanium hydride powder, and the specific steps include:

[0042] S1: Prepare 50 mL of 0.5 mM chloroplatinic acid solution;

[0043] S201: Disperse 100 mg of titanium hydride powder in the solution prepared in 1) and stir at room temperature for 72 h;

[0044] S202: Filter the suspension in S201, wash and dry to obtain a composite material C, i.e., titanium hydride-loaded platinum material;

[0045] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0046] like Figure 1 As shown in Figure 2, the characteristic diffraction peak of platinum appears in the XRD diffraction peak, proving that chloroplatinic acid is reduced to a single substance by titanium hydride; the TEM image proves that platinum nanoparticles are uniformly dispersed on the surface of titanium hydride (such as Figure 2 As shown); Electrochemical tests show that the obtained platinum hydride titanium composite material has better hydrogen evolution catalytic activity than commercial platinum carbon and exhibits excellent electrochemical stability (as shown Figure 3 and Figure 4 This example demonstrates that titanium hydride can significantly enhance the alkaline hydrogen evolution catalytic activity of platinum.

[0047] Example 2

[0048] In this embodiment, the hydrogen evolution catalyst A is molybdenum sulfide, and the transition metal hydride B is titanium hydride powder, and the specific steps include:

[0049] S1: Weigh 40g potassium thiocyanate powder, 412mg sodium molybdate powder, and 320mg titanium hydride powder, mix the raw materials evenly, heat to 320°C and keep the reaction at this temperature for 2 hours;

[0050] S2: washing the solid after the reaction in S1 with water and filtering it, and then vacuum drying it to obtain a composite material C, i.e., a titanium hydride-supported molybdenum sulfide composite material;

[0051] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0052] like Figure 5 As shown, the XRD spectrum is the superposition signal of the diffraction peaks of molybdenum sulfide and titanium hydride, which shows the successful preparation of the titanium hydride supported molybdenum sulfide composite material; Figure 6 The alkaline hydrogen evolution polarization curves of titanium hydride, molybdenum sulfide and the composite material, wherein titanium hydride has no hydrogen evolution activity; however, when molybdenum sulfide is composited with titanium hydride, its hydrogen evolution catalytic activity is significantly improved, showing a beneficial effect; this embodiment illustrates that titanium hydride material without hydrogen evolution activity can improve the alkaline hydrogen evolution catalytic performance of molybdenum sulfide.

[0053] Example 3

[0054] In this embodiment, the hydrogen evolution catalyst A is nickel sulfide powder, and the transition metal hydride B is titanium hydride powder, and the specific steps include:

[0055] S1: Weigh 40 g of potassium thiocyanate powder and 475 mg of nickel chloride powder, mix them evenly, heat the evenly mixed potassium thiocyanate powder and nickel chloride powder to 250° C., and react at this constant temperature for 2 hours, wash the solid after the reaction with water, filter it, and vacuum dry it to obtain hydrogen evolution catalyst A powder, i.e. nickel sulfide powder;

[0056] S2: taking 180 mg of titanium hydride powder, and mechanically mixing it with the nickel sulfide powder obtained in S103 to obtain a composite material C, i.e. a composite material of nickel sulfide and titanium hydride;

[0057] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0058] Figure 7 The alkaline hydrogen evolution polarization curves of titanium hydride, nickel sulfide and composite catalyst are shown in FIG. As can be seen from the figure, titanium hydride can significantly improve the alkaline hydrogen evolution catalytic activity of nickel sulfide through simple mechanical mixing. This example demonstrates the convenience of the technology provided by the present invention.

[0059] Example 4

[0060] In this embodiment, the hydrogen evolution catalyst A is nickel sulfide powder, and the transition metal hydride B is yttrium hydride powder, and the specific steps include:

[0061] S1: Weigh 40 g of potassium thiocyanate powder and 475 mg of nickel chloride powder, mix them evenly, heat the evenly mixed potassium thiocyanate powder and nickel chloride powder to 250° C., and react at this constant temperature for 2 hours, wash the solid after the reaction with water, filter it, and vacuum dry it to obtain hydrogen evolution catalyst A powder, i.e. nickel sulfide powder;

[0062] S2: Take 180 mg of yttrium hydride powder, grind and mix it with the nickel sulfide powder obtained in S103 to obtain a composite material C, i.e., a composite catalyst of nickel sulfide and yttrium hydride;

[0063] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0064] Figure 8 The alkaline hydrogen evolution polarization curves of yttrium hydride, nickel sulfide and their mixtures are shown in Figure 1. As can be seen from the figure, yttrium hydride has almost no hydrogen evolution catalytic activity similar to titanium hydride, but a simple mechanical mixing of yttrium hydride with nickel sulfide can greatly improve the alkaline hydrogen evolution catalytic performance of nickel sulfide.

[0065] Example 5

[0066] In this embodiment, the hydrogen evolution catalyst A is cobalt sulfide powder, and the transition metal hydride B is yttrium hydride powder, and the specific steps include:

[0067] S1: Weigh 40 g of potassium thiocyanate powder and 260 mg of cobalt chloride powder, mix them evenly, heat the evenly mixed potassium thiocyanate powder and nickel chloride powder to 250° C., and react at this temperature for 2 hours, wash the solid after the reaction with water, filter it, and vacuum dry it to obtain hydrogen evolution catalyst A powder, i.e., cobalt sulfide powder;

[0068] S2: Take 180 mg of yttrium hydride powder, grind and mix it with the nickel sulfide powder obtained in S103 to obtain a composite material C, i.e., a composite catalyst of cobalt sulfide and yttrium hydride;

[0069] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0070] Fig. 9 The alkaline hydrogen evolution polarization curves of yttrium hydride, cobalt sulfide and their mixtures. Compared with cobalt sulfide, the hydrogen evolution current density of the composite catalyst is significantly higher than that of the cobalt sulfide material under the same potential conditions, which fully demonstrates that yttrium hydride can improve the alkaline hydrogen evolution catalytic activity of cobalt sulfide.

[0071] Example 6

[0072] In this embodiment, the hydrogen evolution catalyst A is cobalt phosphide powder, and the transition metal hydride B is titanium hydride powder, and the specific steps include:

[0073] S1: weigh 20 mg of cobalt phosphide powder;

[0074] S2: Take 180 mg of titanium hydride powder, mix it evenly with the cobalt phosphide powder weighed in S1, and grind and mix them to obtain a composite material C, i.e., a cobalt phosphide and titanium hydride composite catalyst;

[0075] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0076] In the electrochemical test, the alkaline hydrogen evolution catalytic performance of the cobalt phosphide and titanium hydride composite catalyst is better than that of cobalt phosphide. This example shows that transition metal hydrides are of great benefit to improving the alkaline hydrogen evolution catalytic performance of phosphides.

[0077] Example 7

[0078] In this embodiment, the hydrogen evolution catalyst A is cobalt phosphide powder, and the transition metal hydride B is titanium hydride powder, and the specific steps include:

[0079] S1: weigh 20 mg of cobalt nitride powder;

[0080] S2: Take 180 mg of yttrium hydride powder, mix it evenly with the cobalt nitride powder weighed in S1, and grind and mix them to obtain a composite material C, i.e., a composite catalyst of cobalt nitride and yttrium hydride;

[0081] S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

[0082] Electrochemical tests show that the hydrogen evolution current density of cobalt nitride is greatly improved after mixing with yttrium hydride, indicating that transition metal hydrides can enhance the activity of nitride hydrogen evolution catalysts.

[0083] The present invention is described in detail above through the embodiments, but the contents are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst, characterized in that: The method comprises the following steps: S1: Select or prepare a certain amount of hydrogen evolution catalyst A; S2: taking a certain amount of transition metal hydride B, and compounding it with the hydrogen evolution catalyst A in S1 to obtain a composite material C; S3: Conducting electrochemical tests on the hydrogen evolution catalyst A, transition metal hydride B, and composite material C to obtain a cathode polarization curve for water electrolysis.

2. The method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In S1, the hydrogen evolution catalyst A is a noble metal material or one or more of transition metal phosphides, sulfides, nitrides, borides, etc.

3. The method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In S2, the transition metal hydride B is one or more of titanium hydride, yttrium hydride, samarium hydride, palladium hydride, nickel hydride, etc., which are stable in the hydrogen evolution reaction under alkaline conditions.

4. The method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst according to claim 1, characterized in that: In S2, the composite method of the hydrogen evolution catalyst A and the transition metal hydride B includes two methods, which include growing the hydrogen evolution catalyst A on the surface of the transition metal hydride B or directly mixing the hydrogen evolution catalyst A and the transition metal hydride B.

5. The method for enhancing the efficiency of an alkaline water electrolysis hydrogen evolution catalyst according to claim 4, characterized in that: The mixing method of the hydrogen evolution catalyst A and the transition metal hydride B includes solution mixing, mechanical mixing or grinding mixing.

Images