阅读说明：本技术 一种三维自支撑性水分解制氢电催化剂及其制备方法 (Three-dimensional self-supporting electrocatalyst for preparing hydrogen by water decomposition and preparation method thereof ) 是由 葛性波 梁梓灏 易洪亮 朱晓琪 杨先辉 王政楠 黎志豪 于 2019-09-27 设计创作，主要内容包括：本发明涉及一种用于水分解制氢的电化学催化剂的制备方法,属于能源转化材料制备技术领域。首先制备原子比镍:钛:铜＝4:1:5的三元合金,然后在把合金加工为厚度20μm左右的条带。采用电化学脱合金的方法,对铜选择性腐蚀,制备出三维带有纳米片状的自支撑镍钛铜催化剂。这种电极材料的优势在于：非贵金属原料含量丰富,价格低廉；三维自支撑性结构,无需有机粘合剂；在碱性介质中制氢,在电流密度为10mA/cm<Sup>-2</Sup>和100mA/cm<Sup>-2</Sup>过电位分别为48mV和124mV,且电流密度超过20mA/cm<Sup>-2</Sup>的时候,本发明电极所需的过电位比贵金属Pt/C还好。(The invention relates to a preparation method of an electrochemical catalyst for hydrogen production by water decomposition, belonging to the technical field of energy conversion material preparation. First, a ternary alloy of nickel, titanium and copper in an atomic ratio of 4:1:5 was prepared, and then the alloy was processed into a strip having a thickness of about 20 μm. The electrochemical dealloying method is adopted to selectively corrode copper, and the three-dimensional self-supporting nickel-titanium-copper catalyst with the nano-sheet shape is prepared. The electrode material has the advantages that: the non-noble metal raw material has rich content and low price; a three-dimensional self-supporting structure without the need for organic binders; producing hydrogen in an alkaline medium inThe current density is 10mA/cm ‑2 And 100mA/cm ‑2 The overpotential is 48mV and 124mV, respectively, and the current density exceeds 20mA/cm ‑2 In time, the overpotential required for the electrode of the present invention is better than that of the noble metal Pt/C.)

1. A three-dimensional self-supporting hydrogen production electrocatalyst by water decomposition and a preparation method thereof are characterized by comprising the following steps:

(1) preparing an alloy: preparing a nickel-titanium-copper ternary alloy with an atomic ratio of nickel to titanium to copper of 4:1:5, and processing the alloy into an alloy strip with the width of about 20 mu m;

(2) preparing a porous three-dimensional self-supporting electrode with a nano sheet shape by using the alloy strip prepared in the step 1 through a dealloying method, wherein the nano sheet specification of the three-dimensional self-supporting electrode is about 200-500 nm;

(3) the dealloying method in the step 2 is electrochemical dealloying;

(4) and in the electrochemical dealloying, the alloy strip prepared in the step 1 is used as a working electrode, a three-electrode system is adopted, and 0.6-1.0V potential is applied in 0.5mol/L sulfuric acid for 5-200 seconds.

2. The three-dimensional self-supporting electrocatalyst for hydrogen generation from water decomposition and its preparation method as claimed in claim 1, wherein in ternary alloy nickel titanium copper, applying a certain potential in dilute sulfuric acid solution, performing anodic passivation on nickel and titanium, and selectively etching copper.

3. The three-dimensional self-supporting catalytic electrode prepared by the preparation method according to claims 1-2.

4. The application of the three-dimensional self-supporting catalytic electrode prepared by the preparation method according to the claims 1-2 in the aspect of hydrogen production by water electrolysis.

Technical Field

The invention relates to a preparation method of an electrochemical catalyst for hydrogen production by water decomposition, belonging to the technical field of energy conversion material preparation.

Background

Hydrogen energy is a clean and sustainable energy source. The search for a catalyst which can efficiently and continuously drive water electrolysis to produce hydrogen at low potential is one of the keys for realizing hydrogen economy. At present, noble metals platinum are regarded as the best hydrogen production catalyst, and because noble metals are rare and expensive, the large-scale application of noble metals in the water electrolysis industry is greatly hindered. Therefore, the development of inexpensive non-noble metal catalysts to replace the current noble metal catalysts is an important task at present. In addition, non-noble metal catalysts have poor durability in acidic media, limiting the development of acidic hydrogen production. The alkaline electrolytic cell not only has perfect related technology and certain commercial development space, but also produces hydrogen under alkaline condition, which is one of the key reactions of chlor-alkali process. In order to meet the huge demand of hydrogen energy, the technology of electrolyzing water to produce hydrogen under alkaline conditions is particularly important.

In recent years, the synergistic effect of binary or multi-element metals has attracted the attention of researchers, especially nickel-copper based alloys. But the hydrogen production catalytic activity is limited due to the insufficient exposure of active sites. In addition, the reports indicate that the metal titanium has excellent synergistic effect when combined with copper or nickel. Common electrocatalysts are in powder form and need to rely on organic binders for immobilization on the working electrode. Problems such as limited loading of the powdered catalyst, poor conductivity of the organic binder, and falling off of the powdered catalyst all affect the stability of the electrode. Compared with the prior art, the three-dimensional self-supporting electrode has larger active specific surface area, is beneficial to electron transmission and proton transfer, has high performance and simple preparation process, and has good application prospect. Therefore, the development of the nickel-titanium-copper ternary self-supporting catalyst electrode has great significance.

Disclosure of Invention

The invention aims to reduce the overpotential of hydrogen production by water electrolysis and effectively drive the hydrogen production reaction under alkaline conditions, and provides a porous three-dimensional self-supporting catalyst electrode with cheap raw materials and simple and mild preparation process and a preparation method thereof.

In order to achieve the above object, the present invention adopts the following technical solution, including the steps of:

(1) preparing an alloy: a nickel titanium copper ternary alloy was prepared with an atomic ratio of nickel to titanium to copper of 4:1: 5. The alloy is processed into alloy strips having a width of about 20 μm.

(2) And (3) preparing the porous three-dimensional self-supporting electrode with the nano sheet shape by using the alloy strip prepared in the step (1) through a dealloying method, wherein the nano sheet specification of the three-dimensional self-supporting electrode is about 200-500 nm.

(3) The dealloying method in the step 2 is electrochemical dealloying.

(4) And in the electrochemical dealloying, the alloy strip prepared in the step 1 is used as a working electrode, a three-electrode system is adopted, and 0.6-1.0V potential is applied in 0.5mol/L sulfuric acid for 5-200 seconds.

(5) The three-dimensional self-supporting electrode prepared by the method is applied to hydrogen production by electrolyzing water in an alkaline medium (1 mol/L).

The invention provides a three-dimensional self-supporting electrode and a preparation method thereof, wherein a nickel-titanium-copper ternary alloy is prepared at first, the atomic ratio of nickel to titanium to copper is 4:1:5, electrochemical dealloying in 0.5mol/L utilizes the characteristic that Ni and Ti are easy to be subjected to anodic passivation in dilute sulfuric acid so as to hinder etching, dealloying is carried out on Cu in NTiCu, the proportion of copper is regulated and controlled through etching, so that a flat structure is converted into a porous three-dimensional structure with a nanosheet shape, active sites on the surface are greatly exposed, and the alkaline hydrogen production performance is promoted.

The invention has the beneficial effects that: 1) a porous three-dimensional self-supporting electrode without the need for an organic binder and a supporting electrode; 2) the raw materials are non-noble metals, so that the price is low and the source is wide; 3) has excellent hydrogen evolution catalytic activity, and only needs small overpotential (current density of 10 m) in 1mol/L potassium hydroxideA·cm^-248mV) to drive the hydrogen production reaction to proceed, and can continuously and stably work for 12 hours under the potential of 150mV, which is better than the performance and stability of most of the existing catalysts.

Drawings

FIG. 1 is a graph of the electrochemical dealloying preparation process of the three-dimensional self-supporting catalytic electrode obtained in example 1;

FIG. 2 is an SEM image of a three-dimensional self-supported catalytic electrode obtained in example 1;

FIG. 3 is an EDS diagram of the three-dimensional self-supporting catalytic electrode obtained in example 1;

FIG. 4 is a graph showing hydrogen production from water electrolysis of a three-dimensional self-supporting catalytic electrode and a noble metal Pt/C (20 wt%) at 1mol/L potassium hydroxide obtained in example 1 ((i.e., a current density curve according to the potential of a reversible hydrogen electrode);

FIG. 5 is a graph showing the catalytic stability of the three-dimensional self-supporting catalytic electrode obtained in example 1 for hydrogen production from water electrolysis at 1mol/L of potassium hydroxide (i.e., a current density curve with time at a constant potential).

Detailed description of the preferred embodiments

The invention is further illustrated by the following detailed description of embodiments in conjunction with the drawings in which:

the preparation method of the three-dimensional self-supporting catalytic electrode comprises the following steps:

(1) preparing an alloy: in the argon atmosphere, a mode of arc melting pure nickel, pure copper and pure titanium is adopted, and the nickel-titanium-copper alloy is rapidly solidified and cast at a super-cooling temperature, wherein the atomic ratio of nickel to titanium to copper is 4:1: 5. Thereafter, the alloy was processed into a NiCuTi alloy strip having a thickness of about 20 μm on a melt spinning machine.

(2) And (3) preparing the porous three-dimensional self-supporting electrode with the nano sheet shape by using the alloy strip prepared in the step (1) through a dealloying method, wherein the nano sheet specification of the three-dimensional self-supporting electrode is about 200-500 nm.

(3) The dealloying method in the step 2 is electrochemical dealloying.

(4) And in the electrochemical dealloying, the alloy strip prepared in the step 1 is used as a working electrode, a three-electrode system is adopted, and 0.6-1.0V potential is applied in 0.5mol/L sulfuric acid for 5-200 seconds.

(5) The three-dimensional self-supporting electrode prepared by the method is applied to hydrogen production by electrolyzing water with an alkaline medium (1mol/L potassium hydroxide).