Preparation method of water electrolysis hydrogen production catalyst

Abstract

The invention belongs to the technical field of hydrogen production catalysts, and discloses a preparation method of a water electrolysis hydrogen production catalyst, and the prepared catalyst comprises the following components: La2O3, NiO, CoO, TiO2 and MoS2. The preparation method specifically comprises the following steps: mixing raw materials; performing high-temperature sintering and atomic diffusion; performing crushing; the preparation method comprises the following steps: uniformly mixing raw materials, screening, performing high-temperature sintering and atomic diffusion on the uniformly mixed raw materials through an atmosphere furnace in the steps of high-temperature sintering and atomic diffusion, and specifically, performing atomic diffusion: diffusing La < 3 + > in La2O3 into NiO, CoO and TiO2 crystal lattices. Through high-temperature sintering and temperature-controlled diffusion, during high-temperature sintering, a rare earth element La < 3 + > is diffused into crystal lattices of NiO, CoO and TiO2, electron holes are introduced, the conductivity is enhanced, the adsorption energy of a hydrogen intermediate is optimized, in addition, due to the addition of MoS2, sulfur vacancies at the edge of MoS2 can stabilize the hydrogen intermediate and reduce the reaction overpotential, so that the activity of the catalyst is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production catalysts, and particularly relates to a preparation method of an electrolytic water hydrogen production catalyst. Background Art

[0002] Electrolytic water hydrogen production is a technology that decomposes water (H2O) into hydrogen (H2) and oxygen (O2) through electric energy. It is one of the main ways to produce green hydrogen (hydrogen energy produced using renewable energy) and is also a key link in the clean energy system.

[0003] Its reaction equation is 2H2O—electrolysis→2H2+O2;

[0004] In an alkaline medium, the reactions at the cathode and anode are as follows.

[0005] An oxidation reaction occurs at the anode: 4OH - ——→O2+2H2O+4e - ,OH - Multiple-step oxidation occurs on the catalyst surface to generate oxygen intermediates, which finally combine to form O2;

[0006] A reduction reaction occurs at the cathode: 2H2O+2e - ——→H2+2OH - , water molecules dissociate on the catalyst surface, and the adsorbed hydrogen intermediates combine to form H2.

[0007] The commonly used catalytically active electrode materials for electrolytic water hydrogen production are mainly noble metals and their alloys, mainly platinum group metals such as Pt, Pd, Ru, etc. Pt has excellent catalytic performance, but due to the extreme scarcity and high price of Pt, its large-scale application is limited.

[0008] In addition to platinum group metals, there is also a mixed powder of Ni powder and Al powder, as well as NiAl alloy, which are also commonly used catalytic materials in current electrolytic water hydrogen production electrolyzers. The cost of this catalyst material is low, but during use, it is easily soluble in strong alkaline electrolytes, resulting in too rapid attenuation of the electrode catalyst, with an annual attenuation of up to 20%, far lower than the industry's expectation of an annual attenuation not exceeding 2%. Therefore, this material greatly reduces the operation sales volume and lifespan of the electrolyzer.

[0009] For the above reasons, providing a preparation method of an electrolytic water hydrogen production catalyst to prepare a new catalyst material with good catalytic effect and not easily soluble in strong alkaline electrolytes will help improve the service life and operation stability of the electrolyzer, and thus reduce the cost of electrolytic water hydrogen production. Summary of the Invention

[0010] Aiming at the problems in the existing technology that the use of precious metals incurs high costs, and the use of Ni, Al mixed powder or NiAl alloy results in too fast attenuation, the object of the present invention is to provide a preparation method of an electrolytic water hydrogen production catalyst, which can improve the catalytic activity of the electrode, reduce the dissolution and attenuation rate of the catalyst in a strong alkaline electrolyte, and improve the operation stability and service life of the electrolytic cell.

[0011] To achieve the above technical object, the technical solution adopted by the present invention is as follows:

[0012] A preparation method of an electrolytic water hydrogen production catalyst, the catalyst prepared by high-temperature sintering includes the following components: La2O3, NiO, CoO, TiO2, MoS2.

[0013] In the present invention, during high-temperature sintering, the rare earth element La3+ diffuses into the lattices of NiO, CoO, and TiO2, introducing electron holes, enhancing the conductivity, and optimizing the adsorption energy of hydrogen intermediates (H*);

[0014] In addition, due to the addition of MoS2, the sulfur vacancies at the edges of MoS2 can stabilize hydrogen intermediates (H*), reducing the reaction overpotential, thereby significantly improving the catalyst activity.

[0015] As a preferred technical solution of the present invention, the preparation method specifically includes the following steps:

[0016] (Ⅰ) Mix raw materials;

[0017] (Ⅱ) High-temperature sintering and atomic diffusion;

[0018] (Ⅲ) Crushing;

[0019] (Ⅳ) Screening.

[0020] The present invention specifically limits that the raw materials need to be mixed before high-temperature sintering, and crushing and screening are required after high-temperature sintering. This is because the uniform mixing of raw materials is conducive to the diffusion of atoms during subsequent high-temperature sintering, which is beneficial to improving the uniformity of the catalyst composition; after high-temperature sintering, the catalyst condenses into a whole block. In order to facilitate the subsequent use of the catalyst, such as weighing, packaging, and selling, the catalyst that has condensed into a whole block needs to be dispersed into powder, so crushing is required. The screening after crushing can control the particle size distribution of the catalyst.

[0021] As a preferred technical solution of the present invention, in step (Ⅰ), NiO, CoO, TiO2, MoS2, and La2O3 are mixed evenly by a mixer.

[0022] The present invention specifically specifies that a mixer is used to mix NiO, CoO, TiO2, MoS2, and La2O3 because the mixer has high stirring efficiency and the mixing is relatively uniform, and its feeding and discharging are convenient for operation.

[0023] As a preferred technical solution of the present invention, in step (II), the uniformly mixed raw materials are subjected to high-temperature sintering and atomic diffusion through an atmosphere furnace. Specifically, the atomic diffusion is the diffusion of La3+ in La2O3 into the lattices of NiO, CoO, and TiO2.

[0024] The present invention specifically specifies that an atmosphere furnace is used for high-temperature sintering and atomic diffusion because the atmosphere furnace can accurately control the sintering environment, such as parameters such as the sintering temperature and the internal gas pressure, which is extremely convenient for the control of La3+ diffusion. In addition, the atmosphere furnace has good process repeatability, and the atmosphere furnace can accurately record the temperature-time-atmosphere curve to ensure batch consistency and is suitable for industrial production.

[0025] As a preferred technical solution of the present invention, in step (III), the sintered block catalyst is crushed to obtain a fine-particle powder catalyst; in step (IV), the particle size distribution is controlled by screening.

[0026] The present invention specifically specifies that the sintered block catalyst needs to be crushed and screened in order to disperse the catalyst into a state that is convenient for use, dosing, selling, and packaging, and screening can effectively control the particle size distribution of the catalyst.

[0027] As a preferred technical solution of the present invention, in the prepared catalyst, the mass percentage of La2O3 does not exceed 2%.

[0028] As a preferred technical solution of the present invention, in the prepared catalyst, the mass percentage of MoS2 does not exceed 5%.

[0029] Exemplarily, the present invention provides a method for preparing an electrolytic water hydrogen production catalyst, and the preparation method includes the following steps:

[0030] (1) Mix the raw materials of La2O3, NiO, CoO, TiO2, and MoS2 evenly through a mixer;

[0031] (2) Subject the uniformly mixed raw materials to high-temperature sintering and atomic diffusion through an atmosphere furnace. Specifically, the atomic diffusion is the diffusion of La3+ in La2O3 into the lattices of NiO, CoO, and TiO2;

[0032] (3) Crush the sintered block catalyst to obtain a fine-particle powder catalyst;

[0033] (4) Control the particle size distribution by screening. In the prepared catalyst, the mass percentage of La2O3 does not exceed 2%, and in the prepared catalyst, the mass percentage of MoS2 does not exceed 5%.

[0034] Advantages of the present invention: Through high-temperature sintering and temperature-controlled diffusion, during high-temperature sintering, rare earth element La3+ diffuses into the lattices of NiO, CoO, and TiO2, introducing electron holes, enhancing conductivity, and optimizing the adsorption energy of hydrogen intermediates (H*). In addition, due to the addition of MoS2, sulfur vacancies at the edges of MoS2 can stabilize hydrogen intermediates (H*), reducing the reaction overpotential, thereby significantly improving the catalyst activity; in the performance test, the catalytic activity prepared by the present invention is more active than that of the NiAl alloy, the cell voltage can reach 1.6 V, and in 1000 start-stop acceleration simulation experiments, its decay rate drops to about 2%, significantly lower than 20% of the NiAl alloy. Description of the Drawings

[0035] The present invention can be further illustrated by the non-limiting embodiments given in the drawings;

[0036] Figure 1 It is the process flow chart of the embodiment of the present invention. Detailed Embodiments

[0037] The technical solution of the present invention will be described in detail below in conjunction with specific embodiments and their drawings. The embodiments described herein are specific specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are all explanatory and exemplary, and should not be construed as limiting the embodiments of the present invention and the protection scope of the present invention. Except for the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of the present application, and these technical solutions include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0038] Embodiment

[0039] As Figure 1 shown, this embodiment provides a preparation method of an electrolyzed water hydrogen production catalyst, and the preparation method includes the following steps:

[0040] (1) Mix the raw materials of La2O3, NiO, CoO, TiO2, and MoS2 evenly by a mixer;

[0041] (2) Carry out high-temperature sintering and atomic diffusion on the evenly mixed raw materials through an atmosphere furnace. The specific atomic diffusion is that La3+ in La2O3 diffuses into the lattices of NiO, CoO, and TiO2;

[0042] (3) Crush the sintered bulk catalyst to obtain a fine-particle powder catalyst;

[0043] (4) Control the particle size distribution by sieving. In the prepared catalyst, the mass percentage of La2O3 is 2%, the mass percentage of NiO is 40%, the mass percentage of CoO is 28%, the mass percentage of TiO2 is 25%, and the mass percentage of MoS2 is 5%.

[0044] In this embodiment, through high-temperature sintering and temperature regulation, during high-temperature sintering, rare earth element La3+ diffuses into the lattices of NiO, CoO, and TiO2, introducing electron holes, enhancing conductivity, and optimizing the adsorption energy of hydrogen intermediates (H*);

[0045] In addition, due to the addition of MoS2, sulfur vacancies at the edges of MoS2 can stabilize hydrogen intermediates (H*), reducing the reaction overpotential, thereby significantly enhancing the catalyst activity;

[0046] Perform performance tests on the catalyst obtained in this embodiment;

[0047] Its catalytic activity is more active than that of NiAl alloy;

[0048] The cell voltage can reach 1.6 V;

[0049] In 1000 start-stop acceleration simulation experiments, its decay rate drops to about 2%, significantly lower than 20% of NiAl alloy.

[0050] The above embodiments only exemplarily illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation method of an electrolytic water hydrogen production catalyst, characterized in that: The prepared catalyst comprises the following components: La2O3, NiO, CoO, TiO2, MoS2.

2. The preparation method of an electrolytic water hydrogen production catalyst according to claim 1, characterized in that: The catalyst is prepared by high-temperature sintering.

3. A method for preparing an electrolytic water hydrogen production catalyst according to claim 2, characterized in that: Specifically, it includes the following steps: (Ⅰ) Mix the raw materials; (Ⅱ) High-temperature sintering and atomic diffusion; (Ⅲ) Crushing; (Ⅳ) Screening.

4. A method for preparing an electrolytic water hydrogen production catalyst according to claim 3, characterized in that: In step (Ⅰ), NiO, CoO, TiO2, MoS2 and La2O3 are uniformly mixed by a mixer.

5. The preparation method of an electrolytic water hydrogen production catalyst according to claim 3, wherein: In step (Ⅱ), the uniformly mixed raw materials are subjected to high-temperature sintering and atomic diffusion in an atmosphere furnace. Specifically, the atomic diffusion is the diffusion of La3+ in La2O3 into the lattices of NiO, CoO, and TiO2.

6. The preparation method of an electrolytic water hydrogen production catalyst according to claim 3, characterized in that: In step (Ⅲ), the sintered bulk catalyst is crushed to obtain a fine-particle powder catalyst.

7. A method for preparing an electrolytic water hydrogen production catalyst according to claim 3, characterized in that: In step (Ⅳ), the particle size distribution is controlled by screening.

8. A method for preparing an electrolytic water hydrogen production catalyst according to claim 1, characterized in that: In the prepared catalyst, the mass percentage of La2O3 does not exceed 2%.

9. The preparation method of an electrolytic water hydrogen production catalyst according to claim 8, characterized in that: In the prepared catalyst, the mass percentage of MoS2 does not exceed 5%.

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