阅读说明：本技术 化学镀法制备一种高效电解水析氢催化剂的方法 (Method for preparing efficient electrolytic water hydrogen evolution catalyst by chemical plating method ) 是由 史星伟 张亚娟 张锁江 于 2021-08-20 设计创作，主要内容包括：本发明公开了应用化学镀法制备一种高效电解水析氢催化剂的方法。为改进和提高现有电解水析氢催化剂在碱性电解液中HER的催化活性和稳定性,本发明制备了一种简单、易操作、易于工业化的化学镀沉积的镍-钴-磷高效催化剂,降低了碱性电解水催化剂的过电位,提高了电流密度。该方法包括：配制不同比例的化学镀液,以金属泡沫为基底,在不同反应温度和不同反应时间下沉积得到镍-钴-磷高效复合催化剂。该复合催化剂中,镍-钴-磷活性物质直接沉积在金属泡沫上避免了使用粘结剂,增加了催化剂在碱性电解液中的电化学性能,提高其导电性和稳定性,增加了电子传输速率。本发明制备的催化电极突出的特征是催化剂与基体结合牢固,电化学稳定性好,使用寿命长。(The invention discloses a method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by using a chemical plating method. In order to improve and improve the catalytic activity and stability of the HER in alkaline electrolyte of the existing water electrolysis hydrogen evolution catalyst, the invention prepares the nickel-cobalt-phosphorus high-efficiency catalyst which is simple, easy to operate and easy to industrialize and chemically plate and deposit, reduces the overpotential of the alkaline water electrolysis catalyst and improves the current density. The method comprises the following steps: preparing chemical plating solutions with different proportions, and depositing the chemical plating solutions by taking metal foam as a substrate at different reaction temperatures and different reaction times to obtain the nickel-cobalt-phosphorus efficient composite catalyst. In the composite catalyst, the nickel-cobalt-phosphorus active substance is directly deposited on the metal foam, so that a binder is avoided, the electrochemical performance of the catalyst in alkaline electrolyte is improved, the conductivity and the stability of the catalyst are improved, and the electron transmission rate is increased. The catalytic electrode prepared by the invention has the outstanding characteristics of firm combination of the catalyst and the matrix, good electrochemical stability and long service life.)

1. The method for preparing the efficient water electrolysis hydrogen evolution catalyst by the chemical plating method is characterized by comprising the following steps of:

(1) the metal foam substrate pretreatment process comprises the following steps: the metal foam substrate is ultrasonically cleaned in an acidic solution, an organic solvent and deionized water for several times to remove oxides and impurities on the surface thereof.

(2) The preparation process of the plating solution comprises the following steps: the metal salt, the reducing agent, the complexing agent, the buffering agent and the deionized water in different proportions are weighed and mixed according to a certain proportion, and the chemical plating solution is prepared by uniformly stirring.

(3) Chemical plating experiment: the pretreated substrate in step (1) is immersed in the prepared chemical plating solution in step (2), the chemical plating reaction is carried out at a certain temperature and for a certain time, after the reaction is completed, the catalyst is taken out and repeatedly washed with absolute ethyl alcohol and deionized water for several times, and the prepared catalyst is obtained after drying at a certain temperature.

(4) And (4) taking the catalyst synthesized in the step (3) as a self-supporting electrode, and carrying out an electrolytic water hydrogen evolution performance test on the self-supporting electrode.

2. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the method comprises the following steps: the metal foam substrate in the step (1) is one or two selected from titanium foam, cobalt foam, nickel foam, copper foam, iron foam and stainless steel mesh.

3. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the method comprises the following steps: the acid solution in the step (1) is 1-3M hydrochloric acid solution.

4. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the method comprises the following steps: the organic solution in the step (1) is acetone and absolute ethyl alcohol solution.

5. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the method comprises the following steps: in the step (2) of the chemical plating process, the cation in the metal salt can be Fe²⁺、Mo²⁺、Ni²⁺、Co²⁺、Zn²⁺、Ag²⁺、Sn²⁺、Cu²⁺One or more of the above-mentioned compounds, and the anion can be selected from C1^-、SO₄ ^2-、NO^3-One or more of them. The reducing agent is sodium hypophosphite with the concentration of 5-20 mM, the complexing agent is sodium succinate with the concentration of 0.1-0.2M, the buffering agent is sodium sulfate with the concentration of 0.15-0.2M, and the sodium succinate are uniformly stirred for a certain time.

6. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein in the electroless plating process in the step (2), the molar ratio of two metal salts is respectively 1: 4. 2: 3. 1: 1. 3: 2. 4: 1, the stirring time is 20-30 min.

7. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the reaction temperature in the step (3) is 40-80 ℃, and the reaction time is 5-240 min.

8. The method for preparing a high-efficiency catalyst for hydrogen evolution by electrolysis by an electroless plating method according to claim 1, wherein the drying temperature in the step (3) is 60 ℃.

9. The method for preparing a high-efficiency electrolytic water hydrogen evolution catalyst by an electroless plating method according to claim 1, wherein the electrochemical measurement in the step (4) is tested by using CHI760E electrochemical workstation, the testing temperature is room temperature, and a three-electrode system is adopted, namely a working electrode (catalyst preparation)) An auxiliary electrode (carbon rod) and a reference electrode (Hg/HgO), wherein the area of the catalytic material on the working electrode penetrating into the electrolyte is 1cm²。

Technical Field

The invention belongs to the field of preparation of catalysts for hydrogen production by water electrolysis, and introduces a method for preparing a high-efficiency catalyst for hydrogen production by water electrolysis by a chemical plating method.

Background

In recent years, traditional energy sources such as petroleum and coal are gradually replaced by clean energy sources such as tide and wind power due to the increase of global carbon dioxide emission year by year. However, the clean energy has limitations such as intermittency, randomness, and fluctuation, so that the development of the clean energy is severely limited. The hydrogen energy is used as an energy source with high energy density, has the advantages of wide source, cleanness, recyclability, basically zero pollution, large-scale storage and the like, and has very wide application prospect.

In the water electrolysis process, two core reactions of Oxygen Evolution (OER) and Hydrogen Evolution (HER) exist, and the thermodynamic voltage for water decomposition is 1.23V. However, in the actual water electrolysis process, a voltage higher than 1.23V is often applied to decompose water. The additional applied voltage is primarily used to overcome the intrinsic activation barrier of the cathode and anode. And the high-activity catalyst can reduce overpotential and accelerate reaction rate.

In alkaline electrolytes, various transition metal compound-based materials, such as phosphide, selenide, carbide, sulfide, nitride, and the like, have been studied in order to overcome the disadvantages of low current density, poor stability, and the like in the hydrogen evolution process. The cobalt and nickel metal elements are rich in the earth crust and have the advantages of unique d-electron configuration and the like, so that the cobalt and nickel metal elements are transition metal elements commonly used for preparing the electrolyzed water catalyst at present. In view of the advantages, the invention prepares a series of high-efficiency, cheap and stable hydrogen evolution catalysts based on cobalt and nickel bases. The invention has important practical significance for industrial development in the field.

Disclosure of Invention

In order to solve the problems of large overpotential and poor stability of the existing catalyst, the inventor carries out deep research on the preparation of the high-efficiency electrocatalyst by the chemical plating method, and finds that the hydrogen evolution electrocatalyst with high stability and low overpotential can be prepared by carrying out pretreatment on various metal foam substrates and then depositing the nickel-cobalt-phosphorus metal alloy in situ by the chemical plating method through a large number of experiments.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that:

(1) pretreatment of the metal foam substrate: the method comprises the steps of ultrasonically cleaning a metal foam substrate in 1M HCI to remove surface oxides, cleaning with acetone and ethanol to remove surface stains, and continuously cleaning with deionized water until the surface stains are completely cleaned, so as to finish the pretreatment of the metal foam substrate.

(2) The plating solution preparation step: weighing reducing agent sodium hypophosphite, complexing agent sodium succinate and buffering agent sodium sulfate, dissolving the sodium hypophosphite, complexing agent sodium succinate and buffering agent sodium sulfate in deionized water, weighing metal salts with different proportions, dissolving the metal salts in the solution, and stirring for 30min to completely dissolve and disperse the metal salts.

(3) Chemical plating experiment: dipping the pretreated substrate in the step (1) into the chemical plating solution prepared in the step (2), respectively carrying out chemical plating reaction at 40 ℃, 60 ℃ and 80 ℃ for 5-240 min, taking out the substrate after the reaction is finished, repeatedly washing the substrate with absolute ethyl alcohol and deionized water for several times, and drying the substrate at 60 ℃ to obtain the prepared catalyst Ni-Co-P/NF.

(4) And (3) performing a test by adopting a CHI760E electrochemical workstation at room temperature, and performing an electrolytic water hydrogen evolution performance test by using the Ni-Co-P/NF catalyst synthesized in the step (3) as a self-supporting electrode.

Drawings

FIG. 1 is a scanning electron microscope picture of Ni-Co-P/NF catalyst electroless plating reaction for 60 min;

FIG. 2 is a scanning electron microscope picture of Ni-Co-P/NF catalyst electroless plating reaction for 120 min;

FIG. 3 is a scanning electron microscope picture of Ni-Co-P/NF catalyst electroless plating reaction for 180 min;

FIG. 4 is a scanning electron microscope photograph of Ni-Co-P/NF catalyst electroless plating reaction for 240 min;

FIG. 5 is a polarization curve of Ni-Co-P/NF electroless plating material at different reaction times.

Detailed Description

The metal salt, sodium succinate, sodium hypophosphite and sodium sulfate selected by the method are all commercially available analytical pure products, no further purification treatment is carried out before experiments, and deionized water is self-made by laboratories; the glassware and equipment used are those commonly used in the laboratory.

The first embodiment is as follows: the commercially available nickel foam is cleaned, and the cleaning process comprises acid washing, acetone cleaning and ethanol cleaning. The preparation method of the pickling solution comprises the following steps: 35% concentrated hydrochloric acid: deionized water 1: and 15, ultrasonically cleaning for 30min at room temperature, washing with deionized water after acid cleaning, ultrasonically cleaning for 10-20 min, ultrasonically cleaning with acetone and ethanol for 15min, finally cleaning with deionized water until the surface is clean, and vacuum drying for later use.

Adding 1.5g of sodium sulfate, 2.5g of sodium succinate, 0.094g of sodium hypophosphite and deionized water into a 250mL beaker, adding 100mL of deionized water to obtain a green-pink solution, stirring for 30min to fully dissolve the green-pink solution, weighing 0.2628g of nickel nitrate and 1.1244g of cobalt nitrate respectively, adding the solutions, performing ultrasonic treatment to fully dissolve and disperse the solutions, immersing the treated nickel foam into the prepared chemical plating solution, reacting for 180min at 60 ℃, washing and drying the product to obtain the pink nickel-cobalt-phosphorus/foamed nickel catalyst.

The second embodiment is as follows: the present embodiment is different from the first embodiment in that the electroless plating reaction temperature is changed to 40 ℃, and the rest is the same as the first embodiment.

The third concrete implementation mode: the present embodiment is different from the first embodiment in that the electroless plating reaction temperature is changed to 80 ℃, and the rest is the same as the first embodiment.

The fourth concrete implementation mode: the present embodiment is different from the first embodiment in that the electroless plating reaction time is 60min, and the rest is the same as the first embodiment.

The fifth concrete implementation mode: the present embodiment is different from the first embodiment in that the electroless plating reaction time is changed to 120min, and the rest is the same as the first embodiment.

The sixth specific implementation mode: the present embodiment is different from the first embodiment in that the electroless plating reaction time is 240min, and the rest is the same as the first embodiment.

The seventh embodiment: the difference between the experimental mode and the specific experimental mode is that nickel nitrate hexahydrate is used as a nickel source, the weighed mass is 0.5257g, cobalt nitrate heptahydrate is used as a cobalt source, the weighed mass is 0.8433g, and the rest is the same as that of the specific embodiment mode.

The specific implementation mode is eight: the difference between the experimental mode and the specific experimental mode is that nickel nitrate hexahydrate is used as a nickel source, the weighed mass is 0.6571g, cobalt nitrate heptahydrate is used as a cobalt source, the weighed mass is 0.7078g, and the rest is the same as that of the specific embodiment mode.

The specific implementation method nine: the difference between the experimental mode and the specific experimental mode is that nickel nitrate hexahydrate is used as a nickel source, the weighed mass is 0.7885g, cobalt nitrate heptahydrate is used as a cobalt source, the weighed mass is 0.5622g, and the rest is the same as that of the specific embodiment mode.

The detailed implementation mode is ten: the difference between the experimental mode and the specific experimental mode is that nickel nitrate hexahydrate is used as a nickel source, the weighed mass is 1.0514g, cobalt nitrate heptahydrate is used as a cobalt source, the weighed mass is 0.2811g, and the rest is the same as that of the specific embodiment mode.

The materials were tested for hydrogen by electrowater desorption as follows:

the electrochemical measurement is carried out by adopting a CHI660E electrochemical workstation, the testing temperature is room temperature, the electrode system is a three-electrode configuration, and a catalyst Ni-Co-P/NF, an auxiliary electrode carbon rod and a reference electrode which are respectively prepared by the working electrode are Hg/HgO electrodes; clamping the synthesized Ni-Co-P/NF material by a platinum sheet electrode clamp, wherein the platinum sheet electrode clamp is not in contact with the electrolyte in the reaction tank, the area penetrating into the electrolyte is 1 square centimeter, recording linear scanning voltammetry in 1MKOH solution, and the scanning speed is 2mV s^-1(ii) a The Ni-Co-P/NF material obtained in the first embodiment is utilized to carry out the electrolytic water hydrogen evolution test, and the Ni-Co-P/NF material prepared in the first embodiment has better electrolytic water hydrogen evolution performance and reaches 10mA cm in 1M KOH solution^-2The required voltage was 137 mV.

The present invention may be embodied in other specific forms, and various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.