CN108796535B - Copper-cobalt-molybdenum/nickel foam porous electrode material with trimetal, and preparation method and application thereof - Google Patents

Abstract

The invention discloses a porous electrode material with three metals Cu-Co-Mo/foamed nickel and a preparation method and application thereof. The method comprises: 1) firstly removing the oil stain and oxide layer on the surface of the foamed nickel by using an organic solution and an acid; 2) The copper, cobalt, molybdenum salt compound precursors and the nickel foam are jointly placed in the autoclave for a closed reaction, then washed and dried to obtain the nickel foam with the hydrothermal synthesis product growing on the surface; 3) the nickel foam obtained in step (2) is placed in the autoclave. High temperature calcination in H ₂ atmosphere, followed by natural cooling, the porous electrolyzed water catalyst with trimetal Cu-Co-Mo/foam nickel is obtained. The three-metal alloy in the composite material has strong bonding ability with the base nickel, stable performance under alkaline conditions, and has a large electrochemical active area, which greatly improves the catalytic activity of the material; the preparation method is realized by a solvothermal method. The combination of the three metals and the foamed nickel substrate has the advantages of simple preparation process, low sintering temperature and low energy consumption in the preparation process, and is convenient for industrial production.

Description

A kind of porous electrode material with trimetallic copper-cobalt-molybdenum/nickel foam and preparation method thereof Law and Application

technical field

The invention relates to the technical field of electrolytic water catalytic hydrogen evolution, in particular to a porous electrode material with trimetallic copper-cobalt-molybdenum (Cu-Co-Mo)/nickel foam and a preparation method and application thereof.

Background technique

The limited use of fossil energy and increasing environmental degradation make the development of clean, renewable new energy and energy storage devices a top priority. Hydrogen energy is considered to be an ideal and feasible alternative to fossil fuels due to its high energy density, non-polluting and sustainable utilization. However, hydrogen energy is not an energy resource that exists in large quantities in nature, but needs to be produced. Among the current methods for producing hydrogen, electrolyzed water has a simple preparation process, relatively mature technology, clean and pollution-free, and is one of the well-known and recognized hydrogen production methods. The hydrogen production reaction of water electrolysis occurs on the electrode surface, including two basic half-reactions, the cathodic hydrogen evolution reaction and the anodic oxygen evolution reaction. How to improve the activity of electrode catalytic materials, reduce the overpotential of hydrogen evolution reaction, and improve the stability of electrode materials is the focus and key of research in the field of electrocatalysis. At present, in the electrocatalytic hydrogen evolution reaction, the best hydrogen evolution catalysts are precious metal series such as Pt. However, due to their high price and scarcity of materials, they cannot be widely promoted in the field of electrocatalysis, which severely limits the large-scale commercial application of electrolysis of water for hydrogen production. process. Therefore, the development of low-cost, low overpotential and good stability of high-efficiency hydrogen evolution catalysts and electrode materials for the electrolysis of water is a current research focus.

According to the experimental study, it is found that the main factors affecting the performance of the cathode hydrogen evolution catalyst are geometrical factor (the real surface area of the electrode) and energy factor (the electronic structure of the material). The ideal hydrogen evolution electrode is: the hydrogen evolution overpotential is as low as possible, the catalytic performance is as stable as possible, and the price is as cheap as possible. Similar to other heterogeneous catalysts, the catalytic performance of catalysts for hydrogen evolution reaction is affected by the density of active sites and the reactivity. Factors such as low conductivity, low specific surface area, and instability at operating voltage in current catalysts are important factors that lead to low catalytic activity. reason. Transition metal elements have the advantages of high stability, abundant reserves and low cost, and are expected to be good catalysts for hydrogen evolution reaction. In addition, nickel-based materials have attracted much attention due to their high electrocatalytic activity for hydrogen evolution reaction, strong corrosion resistance, and low price. In the research on nickel-based electrodes, it was found that there are two main factors affecting the performance of the electrode: (1) the composition of the electrode alloy and its composition ratio: when the composition of the electrode alloy reaches a suitable ratio, the electrode can form a chemical bond with the active H and have a suitable (2) The real surface area of the electrode: when the real surface area of the electrode is much larger _than the apparent area, at the same current density Under , the real current density is smaller than the apparent current density, and usually the smaller the current density is, the smaller the overpotential is. In recent years, the types and structures of nickel-based electrodes have been greatly developed in terms of optimizing alloy composition and increasing electrode surface area.

SUMMARY OF THE INVENTION

Based on the above deficiencies in the prior art, the present invention provides a porous electrode material with three-metal copper-cobalt-molybdenum (Cu-Co-Mo)/nickel foam, and a preparation method and application thereof. The three-metal alloy in the composite material and the substrate are Nickel has strong binding ability, good corrosion resistance, and stable performance under alkaline conditions; the preparation method realizes the combination of three metals and foamed nickel substrates through a solvothermal method, the preparation process is simple, the sintering temperature is low, and the energy consumption in the preparation process is low. Facilitate industrial production.

As a preference of the above technical solutions, the present invention provides a porous electrode material with three metals Cu-Co-Mo/nickel foam and its preparation method and application, further including some or all of the following technical features:

A preparation method of a three-metal Cu-Co-Mo/nickel foam porous electrode material, comprising the following steps:

1) Use organic solvent and acid immersion to remove the oil stain and oxide layer on the surface of the foamed nickel, and pretreat the foamed nickel;

2) The copper salt, cobalt salt, molybdenum salt, and deionized water are proportionally configured into copper, cobalt, and molybdenum salt compound precursor solutions, and the copper, cobalt, and molybdenum salt compound precursors and foam nickel are jointly placed in an autoclave and sealed. Reaction, after the reaction finishes, wash and dry, obtain the foam nickel that grows with hydrothermal synthesis product on the surface;

3) The nickel foam obtained in step (2) is calcined at high temperature in an atmosphere of H ₂ , followed by natural cooling, to obtain a porous electrolyzed water catalyst with trimetallic Cu-Co-Mo/nickel foam.

As an improvement of the above technical solution, the molar ratio of copper, cobalt and molybdenum in the copper, cobalt and molybdenum salt compound precursor solution is 1:0.7-1.2:0.2-1.

As an improvement of the above technical solution, the concentration of the copper salt, cobalt salt and molybdenum salt solution in the copper, cobalt and molybdenum salt compound precursor solution is 0.01-0.05mol/L.

As an improvement of the above technical solution, the copper salt is CuCl ₂ , the cobalt salt is Co(NO ₃ ) ₂ , and the molybdenum salt is Na ₂ MoO ₄ .

As an improvement of the above technical solution, the hydrothermal reaction temperature is 100°C to 200°C, and the reaction time is 4 to 12 hours.

As an improvement of the above technical solution, the gas used in the high temperature reduction of the copper, cobalt, molybdenum salt compound precursors and the foamed nickel in the tube furnace is a 5% H ₂ /95% Ar atmosphere at a temperature of 5 to 10° C./min. The heating rate is raised from room temperature to 300-500° C., the reaction is kept for 1-3 hours, and after the reaction is finished, the catalyst is naturally cooled to obtain a Cu-Co-Mo/foam nickel porous electrolyzed water catalyst.

As an improvement of the above technical solution, the purity of the nickel foam used as the material base is above 99.8%, and the areal density is 300-450 g/m ² .

As an improvement of the above technical solution, the pretreatment process of the foamed nickel includes: firstly soaking in one or more solvents of methanol, ethanol, tetrahydrofuran, and chloroform for ultrasonic treatment for 10-50 min, and then soaking in dilute hydrochloric acid for ultrasonic treatment for 10-50 min. After 50 minutes, use deionized water to wash 3 to 4 times after the treatment.

The technical solution of the present application can also be realized in the following manner, and the above-mentioned preparation method is adopted for the porous electrode material with three-metal Cu-Co-Mo/nickel foam.

The technical solution of the present application can also be realized by the application of the trimetallic Cu-Co-Mo/nickel foam porous electrode material in an electrode for hydrogen production from water electrolysis, as an electrode or catalyst for hydrogen production from water electrolysis.

Compared with the prior art, the technical scheme of the present invention has the following beneficial effects:

(1) The present invention adopts foamed nickel as the substrate, which has good corrosion resistance and can enhance the binding ability of the Cu-Co-Mo alloy and the substrate; adopts elements such as copper, cobalt, and molybdenum, which is low in price and stable in performance under alkaline conditions.

(2) The preparation process of the electrode material (Cu-Co-Mo tri-metal porous electrolyzed water catalyst) of the present invention is simple, the sintering temperature is low, the energy consumption in the preparation process is low, and the industrial production is convenient.

(3) The Cu-Co-Mo trimetal porous water electrolysis catalyst prepared by the present invention has a large electrochemical active area, which greatly improves the catalytic activity of the material.

(4) The active composition of the Cu-Co-Mo three-metal porous water electrolysis catalyst prepared by the present invention is an amorphous structure, which has excellent performance and good stability, and can be widely used as an electrode material for alkaline electrolysis of water for hydrogen evolution, with broadly application foreground.

The above description is only an overview of the technical solutions of the present invention, in order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand , in conjunction with the preferred embodiments, the detailed description is as follows.

Description of drawings

In order to describe the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings of the embodiments will be briefly introduced below.

1 is a scanning electron microscope image of the surface morphology of the porous electrode material with three metals Cu-Co-Mo/nickel foam prepared in Example 1 of the present invention;

2 is a scanning electron microscope image of the surface morphology of the porous electrode material with three metals Cu-Co-Mo/nickel foam prepared in Example 2 of the present invention;

3 is a scanning electron microscope image of the surface morphology of the porous electrode material with three metals Cu-Co-Mo/nickel foam prepared in Example 3 of the present invention;

FIG. 4 is a linear sweep voltammogram of porous electrode materials with three metals Cu-Co-Mo/nickel foam prepared in Examples 1-3 of the present invention.

Detailed ways

The specific embodiments of the present invention will be described in detail below. As part of this specification, the principles of the present invention will be illustrated by examples. Other aspects, features and advantages of the present invention will become apparent from the detailed description.

Example 1

The preparation method of the three-metal Cu-Co-Mo/nickel foam porous electrode material according to the present invention specifically includes the following steps:

a. Pretreatment of conductive substrates

Select the cut 1×1cm ² nickel foam and soak it in one or more solvents of methanol, ethanol, tetrahydrofuran, and chloroform for 10-50min ultrasonic treatment, and then use hydrochloric acid solution for ultrasonic treatment for 15 minutes to carry out chemical degreasing. and surface oxides; finally rinse the nickel substrate with deionized water, wherein the concentration of hydrochloric acid used is 1 mol/L.

b. Growth of hydrothermal synthesis products on nickel foam

The three precursors CuCl ₂ , Co(NO ₃ ) ₂ and Na ₂ MoO ₄ were dissolved in 50 mL of deionized water by hydrothermal method to obtain the precursor solutions of copper, cobalt and molybdenum salt compounds, among which Cu, Co and Mo were The molar ratio of these elements was 1:1:0.25, and together with the pretreated nickel foam was placed in an autoclave for a closed reaction, the reaction temperature was 180°C, and the reaction time was 8h. After the reaction, the dried product was washed and dried.

c. High temperature calcination reduction of hydrothermal synthesis products

The above-mentioned nickel foam with hydrothermal synthesis products grown on the surface was calcined and reduced at 500 °C for 1-3 h in a 5% H ₂ /95% Ar atmosphere, and then cooled naturally to obtain a Cu-Co-Mo three-metal porous electrolyzed water catalyst, namely Equipped with three-metal Cu-Co-Mo/nickel foam porous water electrolysis catalyst.

Figure 1 is a scanning electron microscope image of the surface morphology of the trimetallic Cu-Co-Mo/nickel foam porous electrolyzed water catalyst prepared under this raw material ratio.

Example 2

Step a is the same as Example 1

b. Growth of hydrothermal synthesis products on nickel foam

The three precursors CuCl ₂ , Co(NO ₃ ) ₂ and Na ₂ MoO ₄ were dissolved in 50 mL of deionized water by hydrothermal method to obtain the precursor solutions of copper, cobalt and molybdenum salt compounds, among which Cu, Co and Mo were The molar ratio of these elements is 1:1:0.5, and together with the pretreated nickel foam is placed in an autoclave for closed reaction, the reaction temperature is 180 ° C, the reaction time is 8h, and the dried product is washed after the reaction is completed.

c. High temperature calcination reduction of hydrothermal synthesis products

The above-mentioned nickel foam with hydrothermal synthesis products grown on the surface was calcined and reduced at 500 °C for 5 h in a 5% H ₂ /95% Ar atmosphere, and then cooled naturally to obtain a Cu-Co-Mo tri-metal porous electrolyzed water catalyst, which has three Metallic Cu-Co-Mo/Ni foam porous catalyst for water electrolysis.

Figure 2 is a scanning electron microscope image of the surface morphology of the trimetallic Cu-Co-Mo/nickel foam porous electrolyzed water catalyst prepared under this raw material ratio.

Example 3

Step a is the same as Example 1

b. Growth of hydrothermal synthesis products on nickel foam

The three precursors CuCl ₂ , Co(NO ₃ ) ₂ and Na ₂ MoO ₄ were dissolved in 50 mL of deionized water by hydrothermal method to obtain the precursor solutions of copper, cobalt and molybdenum salt compounds, among which Cu, Co and Mo were The molar ratio of these elements is 1:1:1, and together with the pretreated nickel foam is placed in an autoclave for a closed reaction, the reaction temperature is 180 ° C, the reaction time is 8h, and the dried product is washed after the reaction is completed.

c. High temperature calcination reduction of hydrothermal synthesis products

The above-mentioned nickel foam with hydrothermal synthesis products grown on the surface was calcined and reduced at 500 °C for 5 h in a 5% H ₂ /95% Ar atmosphere, and then cooled naturally to obtain a Cu-Co-Mo tri-metal porous electrolyzed water catalyst, which has three Metallic Cu-Co-Mo/Ni foam porous catalyst for water electrolysis.

Figure 3 is a scanning electron microscope image of the surface morphology of the trimetallic Cu-Co-Mo/nickel foam porous electrolyzed water catalyst prepared under this raw material ratio.

Analysis of the results: From the scanning electron microscope photos in Figures 1-3, it can be seen that the active components of the trimetallic Cu-Co-Mo/nickel foam porous electrolysis water catalyst are uniformly loaded on the nickel foam, and are closely combined with the nickel foam substrate, which greatly reduces the cost of the catalyst. The current resistance during the electrolysis of water improves the catalytic performance of the material.

The trimetallic Cu-Co-Mo/foamed nickel porous electrolyzed water catalyst prepared in the above examples 1-3 was applied to catalyze the electrolysis of water to produce hydrogen.

Linear sweep voltammetry curve test of pure nickel foam and trimetallic Cu-Co-Mo/nickel foam porous electrolyzed water catalyst materials prepared respectively in the three examples:

A three-electrode system was used, with 1mol/L KOH as the electrolyte, in which the carbon rod was used as the counter electrode, and the Ag/AgCl was used as the reference electrode. The foamed nickel porous electrolyzed water catalyst materials were tested as working electrodes in turn, in which it was ensured that the pure foamed nickel and the three metal Cu-Co-Mo/foamed nickel porous electrolyzed water catalysts with three feeding ratios had the same geometric area in the measurement. , the test results are shown in Figure 4.

It can be seen from Figure 4 that the initial overpotentials of the three kinds of catalyst materials with trimetal Cu-Co-Mo/nickel foam porous electrolysis water are about 0.223 V, which is much smaller than the initial overpotential value of pure nickel foam. When the current density is 10 mA/cm ² , the performance of the porous electrolytic water catalyst material with trimetal Cu-Co-Mo/nickel foam is greatly improved compared with pure nickel foam. In terms of materials, the use of nickel foam as a conductive substrate can effectively increase the specific surface area of the material, so that the electrolyzed water material has a 3D porous foam skeleton, which greatly increases the electrochemical active area of the material, thereby greatly reducing the hydrogen evolution overpotential of the material, reducing The energy consumption of the material during the electrolysis of water. From the above comparison, it can be concluded that the trimetal Cu-Co-Mo/foam nickel porous electrolysis water catalyst material prepared by the present invention has excellent catalytic performance, and is expected to become a substitute material for precious metal catalysts in the field of electrolysis of water for hydrogen production.

The above are only the preferred embodiments of the present invention, of course, the scope of the rights of the present invention cannot be limited by this. Several improvements and changes are made, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims (8)

1. A preparation method of a trimetal Cu-Co-Mo/foamed nickel porous electrode material is characterized by comprising the following steps:

1) removing oil stains and an oxide layer on the surface of the foamed nickel by using an organic solvent and acid soaking, and pretreating the foamed nickel;

2) preparing a copper salt, a cobalt salt, a molybdenum salt and deionized water into a copper, cobalt and molybdenum salt compound precursor solution according to a proportion, placing the copper, cobalt and molybdenum salt compound precursor and foamed nickel together in an autoclave for closed reaction, and after the reaction is finished, washing and drying to obtain foamed nickel with a hydrothermal synthesis product growing on the surface; the copper salt is CuCl₂The cobalt salt is Co (NO)₃)₂The molybdenum salt is Na₂MoO₄；

3) The foamed nickel obtained in the step 2) is put in H₂Calcining at high temperature in an/Ar atmosphere, and naturally cooling to obtain the trimetal Cu-Co-Mo/foamed nickel porous electrode material; the high-temperature calcination process specifically comprises the following steps: the gas used for reducing the foamed nickel with the surface growing with the hydro-thermal synthesis product obtained in the step 2) in the tubular furnace at high temperature is 5 percent H₂Heating the mixed gas of Ar and 95 percent to 300-500 ℃ from room temperature at the heating rate of 5-10 ℃/min, and reacting for 1-3 hours in a heat preservation way.

2. The preparation method of the trimetal Cu-Co-Mo/foamed nickel porous electrode material as claimed in claim 1, wherein the molar ratio of copper, cobalt and molybdenum in the precursor solution of the copper, cobalt and molybdenum salt compound is 1: 0.7-1.2: 0.2-1.

3. The preparation method of the trimetal Cu-Co-Mo/foamed nickel porous electrode material as claimed in claim 1 or 2, wherein the concentration of the copper salt, cobalt salt and molybdenum salt solution in the copper, cobalt and molybdenum salt compound precursor solution is 0.01-0.05 mol/L.

4. The preparation method of the trimetal Cu-Co-Mo/foamed nickel porous electrode material as claimed in claim 1, wherein the hydrothermal reaction temperature is 100-200 ℃ and the reaction time is 4-12 h.

5. The method as claimed in claim 1, wherein the purity of the foamed nickel used as the material substrate is 99.8% or more, and the areal density is 300-450g/m²。

6. The method of preparing a trimetallic Cu-Co-Mo/nickel foam porous electrode material of claim 1, wherein the nickel foam pretreatment process comprises: firstly, soaking and ultrasonic processing in one or more solvents of methanol, ethanol, tetrahydrofuran and chloroform for 10-50 min, then soaking and ultrasonic processing for 10-50 min by dilute hydrochloric acid, and cleaning for 3-4 times by using deionized water after the processing is finished.

7. A trimetal Cu-Co-Mo/nickel foam porous electrode material obtained by the preparation method according to any one of claims 1 to 6, wherein the preparation method is adopted for the trimetal Cu-Co-Mo/nickel foam porous electrode material.

8. Use of the trimetal Cu-Co-Mo/foamed nickel porous electrode material obtained by the preparation method according to any one of claims 1 to 6 in an electrode for hydrogen production by water electrolysis.

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