阅读说明：本技术 一种高效电解水的双功能催化剂及其制备方法与应用 (Bifunctional catalyst for efficiently electrolyzing water, and preparation method and application thereof ) 是由 陈燕 何祖韵 朱云敏 靳世广 刘秋宇 于 2020-03-22 设计创作，主要内容包括：本发明公开了一种高效电解水的双功能催化剂及其制备方法与应用。该方法包括：将三维纳米结构模板在过电位条件下进行活化；将活化后的三维纳米结构模版浸泡在过渡金属盐溶液中进行离子吸附处理,取出,得到所述高效电解水的双功能催化剂。本发明提供的高效电解水的双功能催化剂原料价格低廉,无需高温烧结,生产过程耗能较少,生产成本低；该方法采用过渡金属离子吸附策略,制备过程简单,适用于大规模生产。本发明提供的高效电解水的双功能催化剂具有高效的电解水分解性能,在氢析出反应中,在10mA/cm<Sup>2</Sup>的电流密度下的过电位为139 mV,在氧析出反应中,在10mA/cm<Sup>2</Sup>的电流密度下的过电位为239 mV。(The invention discloses a bifunctional catalyst for efficiently electrolyzing water, a preparation method and application thereof. The method comprises the following steps: activating the three-dimensional nano-structure template under an overpotential condition; and soaking the activated three-dimensional nanostructure template in a transition metal salt solution for ion adsorption treatment, and taking out to obtain the high-efficiency electrolyzed water bifunctional catalyst. The bifunctional catalyst for efficiently electrolyzing water provided by the invention has the advantages of low raw material price, no need of high-temperature sintering,the production process has less energy consumption and low production cost; the method adopts transition metal ion adsorption strategy, has simple preparation process, and is suitable for large-scale production. The bifunctional catalyst for efficiently electrolyzing water provided by the invention has high-efficiency electrolytic water decomposition performance, and is 10mA/cm in hydrogen evolution reaction 2 The overpotential at the current density of (a) is 139 mV at 10mA/cm in the oxygen evolution reaction 2 The overpotential at the current density of (a) is 239 mV.)

1. A preparation method of a bifunctional catalyst for efficiently electrolyzing water is characterized by comprising the following steps:

(1) activating the three-dimensional nanostructure template under an overpotential condition to obtain an activated three-dimensional nanostructure template;

(2) and (2) soaking the activated three-dimensional nanostructure template in the step (1) in a transition metal salt solution for ion adsorption treatment, and taking out to obtain the high-efficiency electrolyzed water bifunctional catalyst.

2. The preparation method of the bifunctional catalyst for high efficiency water electrolysis according to claim 1, wherein the three-dimensional nanostructure template in step (1) is a molybdenum disulfide nanosheet or a carbon nanotube array.

3. The method for preparing the bifunctional catalyst for electrolyzing water with high efficiency as claimed in claim 1, wherein the potential of the activation treatment in step (1) is-0.4V to-0.6V vs.

4. The method for preparing a bifunctional catalyst for high efficiency water electrolysis according to claim 1, wherein the activation treatment time in step (1) is 100-500 s.

5. The method for preparing a bifunctional catalyst for efficient electrolysis of water according to claim 1, wherein the transition metal salt solution in step (2) is a nickel acetate solution, a ferrous sulfate solution or a mixed solution of the two.

6. The method for preparing a bifunctional catalyst for efficient electrolysis of water according to claim 1, wherein the concentration of the transition metal salt solution of step (2) is 30-50 mM.

7. The method for preparing a bifunctional catalyst for highly efficient electrolysis of water according to claim 1, wherein the time of the ion adsorption treatment in step (2) is 10 s-20 min.

8. A bifunctional catalyst for efficient electrolysis of water prepared by the preparation method as claimed in any one of claims 1 to 7.

9. Use of the bifunctional catalyst for high efficiency electrolysis of water according to claim 8 in reactions for electrolysis of water.

Technical Field

The invention belongs to the technical field of electrocatalysis materials, and particularly relates to a bifunctional catalyst for efficiently electrolyzing water, and a preparation method and application thereof.

Background

Currently, hydrogen is attracting attention as the highest energy density energy carrier among many new energy feedstocks. The hydrogen energy has high energy density, cleanness, zero pollution and wide source, and has wide prospect in the field of new energy development. At present, a large source of hydrogen is cracking of fossil fuels such as petroleum, and the main disadvantages include limited raw materials, severe energy consumption in the preparation process, low purity of the prepared hydrogen, and the like. The biggest disadvantage is that the hydrogen obtained by cracking the fossil fuel still contains S, P and other impurities, and further desulfurization is needed through a subsequent complex process, so that the production cost is additionally increased, and the desulfurization is not thorough and is extremely easy to poison catalysts such as Pt in a hydrogen energy utilization device. The most desirable way to produce hydrogen is by electrolysis of water. On one hand, the raw materials are simple and easy to obtain, and can be applied in a large scale to convert scattered energy such as solar energy and wind energy into hydrogen energy for storage, and on the other hand, the prepared hydrogen is pure, further desulfurization is not needed, and the process is simple.

The hydrogen production by water electrolysis is mainly divided into two half reactions, wherein the anode generates Oxygen Evolution Reaction (OER) and the cathode generates Hydrogen Evolution Reaction (HER). At present, the catalyst for efficiently electrolyzing water to prepare hydrogen is mainly made of noble metal and noble metal oxide. For the OER reaction, the primary catalyst used is IrO₂And RuO₂And the like, for HER reactions, catalysts mainly usedPt and Pt alloy, etc. However, the noble metal-based catalyst has the disadvantages of scarce raw materials, high price, easy poisoning and difficult large-scale application in practical application. In recent years, many researchers have been working on the development of catalysts containing no noble metal elements, in which the advantages of low price and excellent performance of transition metal compounds are considered to have a great potential to compete with noble metals, and thus, the catalysts are the first commercial catalysts for next generation HER or OER.

However, most of the current transition metal compound catalysts are quite complicated in preparation process, involve high-temperature calcination and other processes, consume much energy, and are difficult to produce on a large scale (Wu, Y.; Li, F.; Chen, W.; Xiaoang, Q.; Ma, Y.; Zhu, H.; Tao, P.; Song, C.; Shang, W.; Deng, T.; Wu, J.; Coupling interfacial compositions of MoS.)₂/Fe₅Ni₄S₈Heterostructures for Efficient ElectrochemicalWater Splitting.Adv Mater2018,30(38) E 1803151.). For example, An et al (An, L.; Feng, J.; Zhang, Y.; Wang, R.; Liu, H.; Wang, G. -C.; Cheng, F.; Xi, P.; epitaxialterogeneous intermediates on N-NiMoO)₄/NiS₂Nanowires/Nanosheets to BoostHydrogen and Oxygen Production for Overall Water Splitting.Advanced Functional Materials2019,29(1) 1805298.) NiMoO was synthesized first by using a solvothermal method₄As precursor, then in turn at NH₃Calcining at high temperature under the atmosphere and the S atmosphere to carry out nitrogen doping and partial vulcanization on the mixed solution to obtain the composite electrocatalyst N-NiMoO₄/NiS₂Used for electrolytic water decomposition. The method involves multi-step reaction, the preparation process is quite complex, high-temperature calcination is needed, the energy consumption is serious, the preparation cost is high, and large-scale commercial production is difficult to realize. Moreover, part of the transition metal compound catalyst only has catalytic action on a single reaction (HER or OER), which requires different electrode catalysts to be adopted at two poles of the hydrogen energy equipment in practical use, thereby increasing the complexity of the design and preparation of the hydrogen energy equipment. Therefore, it is important to develop a bifunctional catalyst with low cost, simple preparation, high performance, and high OER catalytic activity and HER catalytic activity.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a bifunctional catalyst for efficiently electrolyzing water as well as a preparation method and application thereof.

In view of the above disadvantages and shortcomings of the prior art, the primary object of the present invention is to provide a simple method for preparing a bifunctional catalyst for efficient electrolysis of water.

It is another object of the present invention to provide the use of the above bifunctional catalyst in the electrolysis of water.

The purpose of the invention is realized by at least one of the following technical solutions.

A simple and efficient bifunctional catalyst for water electrolysis is prepared by adopting a three-dimensional nano structure as a template, activating the three-dimensional nano structure under a certain overpotential, and then carrying out transition metal ion loading on the activated three-dimensional nano structure by an ion adsorption strategy to prepare the efficient catalyst for water electrolysis.

The invention provides a preparation method of a bifunctional catalyst for efficiently electrolyzing water, which comprises the following steps:

(1) preparing a three-dimensional nano-structure template on a carbon cloth substrate by a hydrothermal synthesis method; activating the three-dimensional nanostructure template under an overpotential condition to obtain an activated three-dimensional nanostructure template;

(2) and (2) soaking the activated three-dimensional nanostructure template in the step (1) in a transition metal salt solution for ion adsorption treatment, and taking out to obtain the high-efficiency electrolyzed water bifunctional catalyst.

Further, the three-dimensional nanostructure template in the step (1) is a molybdenum disulfide nanosheet or a carbon nanotube array.

Preferably, the three-dimensional nanostructure template in step (1) is a molybdenum disulfide nanosheet grown on carbon cloth.

Further, the potential of the activation treatment in the step (1) is-0.4V to-0.6V vs.

Preferably, the potential of the activation treatment of step (1) is-0.5V vs.

Further, the time of the activation treatment in the step (1) is 100-500 s.

Further, the transition metal salt solution in the step (2) is more than one of a nickel acetate solution and a ferrous sulfate solution. Namely, the transition metal salt solution in the step (2) is a nickel acetate solution, a ferrous sulfate solution or a mixed solution of the nickel acetate solution and the ferrous sulfate solution which are uniformly mixed.

Further, the concentration of the transition metal salt solution in the step (2) is 30-50 mM.

Further, the time of the ion adsorption treatment in the step (2) is 10 s-20 min.

The invention provides a bifunctional catalyst for high-efficiency water electrolysis prepared by the preparation method.

The bifunctional catalyst prepared by the invention has the advantages of simple preparation process, energy-saving preparation process, low preparation cost, strong universality of the preparation method, flexible and controllable preparation process, easy regulation of the components of the obtained catalyst and the like, and has high-efficiency electrolytic water decomposition performance.

The bifunctional catalyst for efficiently electrolyzing water provided by the invention can be applied to water electrolysis reaction.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the bifunctional catalyst for efficiently electrolyzing water provided by the invention has the advantages of low raw material price, no need of high-temperature sintering, less energy consumption in the production process and low production cost;

(2) the bifunctional catalyst for efficiently electrolyzing water provided by the invention adopts a transition metal ion adsorption strategy, has a simple preparation process, and is suitable for large-scale production;

(3) the three-dimensional nanostructure template adopted by the high-efficiency water electrolysis bifunctional catalyst provided by the invention is wide in selection, such as a molybdenum disulfide nanosheet, a carbon nanotube array and the like, and the application range is wide;

(4) the bifunctional catalyst for efficiently electrolyzing water provided by the invention adopts a metal ion adsorption strategy, is not influenced by ion species, can be used for easily preparing various transition metal compound catalysts according to requirements, and has universality;

(5) the bifunctional catalyst for efficiently electrolyzing water provided by the invention adopts a metal ion adsorption strategy, can easily prepare composite catalysts with different transition metal ion ratios, and has wide application range;

(6) the bifunctional catalyst for efficiently electrolyzing water provided by the invention has high-efficiency electrolytic water decomposition performance, and is 10mA/cm in hydrogen evolution reaction²The overpotential at the current density of (a) is 139 mV at 10mA/cm in the oxygen evolution reaction²The overpotential at the current density of (a) is 239 mV. In the two-electrode full-hydrolytic reaction, the voltage can reach 10mA/cm under 1.64V²The current density of (2) can reach 100 mA/cm under the voltage of 1.72V²The current density of (1).

Drawings

FIG. 1 is an X-ray photoelectron spectrum of the Ni 2p orbital of the bifunctional catalyst for high efficiency electrolysis of water obtained in example 1;

FIG. 2(a) is a linear sweep voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for catalytic test of hydrogen evolution reaction;

FIG. 2(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for a catalytic test of hydrogen evolution reaction;

FIG. 2(c) is an AC impedance diagram of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for the catalytic test of hydrogen evolution reaction;

FIG. 3(a) is a cyclic voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for catalytic test of oxygen evolution reaction;

FIG. 3(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for catalytic test of oxygen evolution reaction;

FIG. 3(c) is an AC impedance diagram of the bifunctional catalyst for efficient electrolysis of water obtained in example 1 for catalytic test of oxygen evolution reaction;

FIG. 4 is an X-ray photoelectron spectrum of the Fe 2p orbital of the bifunctional catalyst for high efficiency electrolysis of water obtained in example 2;

FIG. 5(a) is a linear sweep voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for catalytic test of hydrogen evolution reaction;

FIG. 5(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for a catalytic test of hydrogen evolution reaction;

FIG. 5(c) is an AC impedance diagram of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for the catalytic test of hydrogen evolution reaction;

FIG. 6(a) is a cyclic voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for catalytic test of oxygen evolution reaction;

FIG. 6(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for catalytic test of oxygen evolution reaction;

FIG. 6(c) is an AC impedance diagram of the bifunctional catalyst for efficient electrolysis of water obtained in example 2 for catalytic test of oxygen evolution reaction;

FIG. 7 is an X-ray photoelectron spectrum of Ni 2p orbitals and Fe 2p orbitals of the bifunctional catalyst for efficient electrolysis of water obtained in example 3;

FIG. 8(a) is a linear sweep voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 3 for catalytic test of hydrogen evolution reaction;

FIG. 8(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 3 for a catalytic test of hydrogen evolution reaction;

FIG. 8(c) is an AC impedance diagram of the bifunctional catalyst for efficient electrolysis of water obtained in example 3 for the catalytic test of hydrogen evolution reaction;

FIG. 9(a) is a cyclic voltammogram of the bifunctional catalyst for efficient electrolysis of water obtained in example 3 for catalytic test of oxygen evolution reaction;

FIG. 9(b) is a Tafel plot of the bifunctional catalyst for efficient electrolysis of water obtained in example 3 for catalytic test of oxygen evolution reaction;

FIG. 9(c) is an AC impedance diagram of the bifunctional catalyst for electrolyzing water with high efficiency obtained in example 3 for the catalytic test of oxygen evolution reaction.

Detailed Description

The following description of the embodiments of the present invention is provided in connection with the accompanying drawings and examples, but the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.