CN115896811A

CN115896811A - Ni-Se-C hydrogen evolution electrode and preparation method thereof

Info

Publication number: CN115896811A
Application number: CN202211499307.1A
Authority: CN
Inventors: 吴艺辉; 孙泽生; 王宇鑫; 何震; 尹丽; 郭平义
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2022-11-28
Filing date: 2022-11-28
Publication date: 2023-04-04

Abstract

The invention discloses a Ni-Se-C hydrogen evolution electrode and a preparation method thereof, belonging to the technical field of electrocatalytic hydrogen evolution. The Ni-Se-C hydrogen evolution electrode consists of a conductive substrate and a Ni-Se-C plating layer electrodeposited on the surface of the conductive substrate. Firstly, preprocessing a conductive substrate; then Ni, se and C elements are deposited on the pretreated conductive substrate in an electrodeposition mode to form the Ni-Se-C hydrogen evolution electrode with excellent hydrogen evolution performance. The synthetic method is simple, the catalyst layer structure is stable, and the synthesized Ni-Se-C hydrogen evolution electrode can be widely applied to the water electrolysis hydrogen production industry and has obvious practical value and economic value.

Description

Ni-Se-C hydrogen evolution electrode and preparation method thereof

Technical Field

The invention relates to a Ni-Se-C hydrogen evolution electrode, in particular to a preparation method of the Ni-Se-C hydrogen evolution electrode.

Background

Under the carbon neutralization target background, the renewable energy is coupled to generate electricity to produce hydrogen, and peak-valley electricity consumption and distributed energy comprehensive application can be realized. The hydrogen energy is used as a bridge for transition and conversion between fossil energy and renewable energy, is expected to reduce carbon emission in the transportation process, and is used for reducing the carbon emission in the metallurgical industry instead of coke. The hydrogen production by water electrolysis is an industrial hydrogen production mode which is widely applied and has mature technology, but the hydrogen production by water electrolysis is influenced by factors such as overpotential and the like, and usually a large amount of electric energy is consumed, thus the large-scale application of the technology is seriously hindered.

In recent years, the development of low-cost non-noble metal electrocatalysts is an effective method for reducing the energy consumption of hydrogen production by water electrolysis. Patent CN114703506A discloses a micron spherical MnFe ₂ O ₄ Nano wire loaded WS ₂ A composite material electro-catalysis hydrogen production catalyst and a preparation method thereof. The catalyst synthesized by the method has a high specific surface area, so that the catalyst has high hydrogen evolution performance, however, the preparation steps are complicated, the synthesized catalyst material is a powder material, and an organic binder is required to be loaded on a substrate material, so that the charge transfer speed is reduced.

Patent CN115011995a discloses a cerium-based hydrogen evolution electrocatalyst, and a preparation method and application thereof. The method has the advantage of simple operation, but the hydrogen evolution overpotential is high, and the requirement of hydrogen production by industrial water electrolysis is difficult to meet.

Disclosure of Invention

The purpose of the invention is as follows: one of the purposes of the invention is to provide a Ni-Se-C hydrogen evolution electrode with high catalytic activity; another object of the present invention is to provide a method for producing the above-mentioned hydrogen evolution electrode.

The technical scheme is as follows: the Ni-Se-C hydrogen evolution electrode consists of a conductive substrate and a Ni-Se-C plating layer electrodeposited on the surface of the conductive substrate.

The electronic structure of the Se atom is 4s2 ⁴ p ⁴ In the middle hollowThe energy level of the 3d orbital is very close to that of the 3s and 3p orbitals, so that the 3d orbital of the Se atom is easily combined with the transition metal atom to form a covalent bond, so that the Se atom has more metal characteristics and is beneficial to the transmission of electrons and the occurrence of catalytic reaction; in addition, the addition of carbon atoms enables the grain size to be finer, so that active sites are increased, and the hydrogen evolution reaction is accelerated.

Wherein in the Ni-Se-C plating layer, the mass percentage of each element is as follows: 40-60% Ni, 40-60% Se and the balance C.

Wherein, the conductive substrate is a foam nickel substrate.

The preparation method of the electrocatalytic hydrogen evolution electrode comprises the following steps:

(1) Firstly, preparing an electroplating aqueous solution, wherein the electroplating aqueous solution is prepared by adding a nickel source, a selenium source, a carbon source, a buffering agent and a conductive agent into water;

(2) Taking the pretreated conductive matrix as a working electrode, a graphite sheet as an auxiliary electrode and a saturated calomel electrode as a reference electrode, and carrying out electrodeposition in an electroplating aqueous solution by adopting an electrodeposition method to obtain a Ni-Se-C coating on the surface of the conductive matrix.

Wherein in the step (1), the nickel source is one or a mixture of several of water-soluble nickel salts; the selenium source is one or a mixture of several of selenium dioxide, sodium selenite and sodium selenate; the carbon source is one or a mixture of arginine, lysine or histidine.

Wherein, in the step (1), the buffer is boric acid or ammonium chloride.

In the step (1), the conductive agent is one or a mixture of NaCl, liCl or KCl.

In the step (1), in the electroplating aqueous solution, the mass concentration of a nickel source is 20-40 g/L, the mass concentration of a selenium source is 5-20 g/L, the mass concentration of a carbon source is 2-5 g/L, and the addition of the carbon source reduces the grain size of the coating, which causes the increase of active sites of intercrystalline substances/grain boundaries and the reduction of hydrogen evolution overpotential; the mass concentration of the buffering agent is 20-60 g/L, and the mass concentration of the conductive agent is 1-10 g/L.

In the step (2), the electroplating deposition mode is CV electrodeposition, porous deposits are generated in the CV electrodeposition process (which is discontinuous in the potential range and interrupted in the circulating process), the contact area of the catalyst is increased, and the reaction rate is accelerated; in the process of electrodeposition, the temperature of the electroplating aqueous solution is 25-50 ℃.

Wherein, in the step (2), the circulating potential in CV electrodeposition is-2 to 0.4V; the scanning speed is 2-10 mV/s; the number of cycles is 3-11. Under the process parameters, the obtained coating is uniform, the crystal grains are fine, and the hydrogen evolution performance is excellent.

Has the beneficial effects that: compared with the prior art, the invention has the following remarkable effects: (1) The Ni-Se-C hydrogen evolution electrode synthesized by the method has low hydrogen evolution overpotential and can be used as an alkaline electrolysis water hydrogen evolution electrode material; (2) The invention adopts CV electrodeposition method, can change the current direction periodically in the course of CV electrodeposition, the sample to be plated becomes the positive pole in a part of time in each period, thus control the time of crystal growth, make it can't grow very thick, in addition the rational electroplating aqueous solution formulation, has improved the polarization of the negative pole, make the generating speed of the crystal nucleus greater than the growing speed of the crystal nucleus, thus the cladding that obtains is crystallized meticulously, the grain size is tiny, the thickness is homogeneous; (3) Before the electrodeposition process, firstly, oxide skin and organic matters on the surface of the substrate are removed through pretreatment, and in addition, the good process parameters are selected, so that the coating is uniformly dispersed and tightly combined with the substrate, the falling phenomenon of the electrode material in the hydrogen evolution reaction process is reduced, and the stability of the electrode is greatly improved.

Drawings

FIG. 1 is a scanning electron micrograph of a Ni-Se-C plating layer prepared in example 1;

FIG. 2 is a graph showing an energy spectrum of the Ni-Se-C plating layer obtained in example 1;

FIG. 3 is a graph of the linear voltammetry (LSV) of Ni-Se-C hydrogen evolution electrodes prepared in examples 1 to 3;

fig. 4 is a graph of the linear voltammetry (LSV) of the hydrogen evolution electrodes prepared in example 1 and comparative examples 1 to 3.

Detailed Description

Example 1

The preparation method of the Ni-Se-C hydrogen evolution electrode specifically comprises the following steps:

(1) Pretreatment of the conductive matrix: cutting a foamed nickel material into small rectangular sheets, chemically removing oil from the cut foamed nickel material by ultrasonic oscillation in absolute ethyl alcohol for 20min, then washing the nickel material with deionized water, then removing oxide on the surface of the material by ultrasonic oscillation in dilute hydrochloric acid with the mass fraction of 10% for 20min, finally washing the nickel material with deionized water until the pH value of the washing effluent is neutral, and putting the nickel material into a vacuum drying box for storage for later use, wherein the pretreatment is to remove oxide skin and organic matters on the surface of a substrate and strengthen the binding force between a plating layer and a conductive substrate;

(2) Preparing an electroplating aqueous solution: adding NiSO into deionized water ₄ ·6H ₂ O、SeO ₂ Lysine, NH ₄ And Cl and LiCl to obtain an electroplating aqueous solution, wherein the mass concentration of each substance in the electroplating aqueous solution is as follows: 30g/LNiSO ₄ ·6H ₂ O、11g/L SeO ₂ 4g/L lysine, 26g/L NH ₄ Cl and 4g/L LiCl; the pH value of the electroplating aqueous solution is 2 (precipitation can occur under alkaline condition, and the electro-catalysis performance of the plating layer is best under strong acid condition);

(3) Preparing a Ni-Se-C hydrogen evolution electrode by adopting a three-electrode system through electrodeposition on an electrochemical workstation, taking foamed nickel as a working electrode, a graphite sheet as an auxiliary electrode and a saturated calomel electrode as a reference electrode, wherein the temperature of an electroplating aqueous solution in the electroplating deposition process is 30 ℃; the circulating potential in CV electrodeposition is-1 to 0.2V, the scanning speed in CV electrodeposition is 5mV/s, and the number of circulating circles in CV electrodeposition is 9 circles; and taking out the foamed nickel after the electroplating deposition is finished, washing the foamed nickel by using distilled water until the pH value of residual liquid is neutral, and drying the foamed nickel for 12 hours at 70 ℃ in a vacuum environment to finally obtain the Ni-Se-C hydrogen evolution electrode.

The Ni-Se-C hydrogen evolution electrode prepared in example 1 was subjected to morphological analysis by a scanning electron microscope, and as can be seen from fig. 1, the electrode surface prepared by CV electrodeposition exhibited a uniform, dense and fine structure with nanoparticles having a very small size, which could provide abundant active sites, and the presence of a cellular structure increased the specific surface area of the electrode, thereby providing the electrode with high hydrogen evolution performance.

FIG. 2 is an energy spectrum of the Ni-Se-C plating layer, and it can be seen from FIG. 2 that Ni, C, and Se elements exist in the plating layer, and the ratio of Ni: se: the atomic ratio of C is 30.13:62.29:7.58 (atomic%)

An electrochemical workstation (Autolab, wantong, switzerland, china ltd) was used to perform electrochemical performance testing on the Ni-Se-C hydrogen evolution electrode material prepared in example 1 in a three-electrode system, with the Ni-Se-C hydrogen evolution electrode as the working electrode, the graphite sheet as the auxiliary electrode, and the SCE as the reference electrode. A hydrogen evolution linear scanning curve is tested by taking a 1mol/L KOH solution as an electrolyte under the conditions that the temperature is 25 ℃ and the scanning speed is 1mV/s, and the curve is shown in figure 3.

Example 2

(1) Pretreatment of the conductive substrate: cutting a foamed nickel material into small rectangular sheets, chemically removing oil from the cut foamed nickel material by ultrasonic oscillation in absolute ethyl alcohol for 20min, then cleaning the material by deionized water, then removing oxide on the surface of the material by ultrasonic oscillation in dilute hydrochloric acid with the mass fraction of 10% for 20min, finally washing the material by deionized water until the pH value of the cleaning effluent is neutral, and placing the material into a vacuum drying oven for storage for later use;

(2) Preparing an electroplating aqueous solution: adding NiSO into deionized water ₄ ·6H ₂ O、SeO ₂ Lysine, NH ₄ And Cl and LiCl to obtain an electroplating aqueous solution, wherein the mass concentration of each substance in the electroplating aqueous solution is as follows: 30g/LNiSO ₄ ·6H ₂ O、11g/L SeO ₂ 3g/L lysine, 26g/L NH ₄ Cl and 4g/L LiCl; the pH value of the electroplating aqueous solution is 2;

(3) Preparing a Ni-Se-C hydrogen evolution electrode by adopting a three-electrode system on an electrochemical workstation through electrodeposition, taking foamed nickel as a working electrode, a graphite sheet as an auxiliary electrode and a saturated calomel electrode as a reference electrode, wherein the temperature of an electroplating aqueous solution in an electroplating deposition process is 30 ℃; the circulating potential in CV electrodeposition is-1 to 0.2V, the scanning speed in CV electrodeposition is 5mV/s, and the number of circulating circles in CV electrodeposition is 9 circles; and taking out the foamed nickel after the electroplating deposition is finished, washing the foamed nickel by using distilled water until the pH value of residual liquid is neutral, and drying the foamed nickel for 12 hours at 70 ℃ in a vacuum environment to finally obtain the Ni-Se-C hydrogen evolution electrode.

An electrochemical workstation (Autolab, wantong, switzerland, china ltd) was used to perform electrochemical performance testing on the Ni-Se-C hydrogen evolution electrode material prepared in example 2 in a three-electrode system, with the Ni-Se-C hydrogen evolution electrode as the working electrode, the graphite sheet as the auxiliary electrode, and the SCE as the reference electrode. A hydrogen evolution linear scanning curve is tested by taking a 1mol/L KOH solution as an electrolyte under the conditions that the temperature is 25 ℃ and the scanning speed is 1mV/s, and the curve is shown in figure 3.

Example 3

(2) Preparing an electroplating aqueous solution: adding NiSO into deionized water ₄ ·6H ₂ O、SeO ₂ Lysine, NH ₄ And Cl and LiCl are used for obtaining an electroplating aqueous solution, and the mass concentration of each substance in the electroplating aqueous solution is as follows: 30g/LNiSO ₄ ·6H ₂ O、11g/LSeO ₂ 2g/L lysine, 26g/L NH ₄ Cl and 4g/L LiCl; the pH value of the electroplating aqueous solution is 2;

(3) Preparing a Ni-Se-C hydrogen evolution electrode by adopting a three-electrode system through electrodeposition on an electrochemical workstation, taking foamed nickel as a working electrode, a graphite sheet as an auxiliary electrode and a saturated calomel electrode as a reference electrode, wherein the temperature of an electroplating aqueous solution in the electroplating deposition process is 30 ℃; the circulating potential in CV electrodeposition is-1 to 0.2V, the scanning speed in CV electrodeposition is 5mV/s, and the number of circulating circles in CV electrodeposition is 9 circles; and taking out the foamed nickel after the electroplating deposition is finished, washing the foamed nickel with distilled water until the pH value of residual liquid is neutral, and drying the foamed nickel for 12 hours at 70 ℃ in a vacuum environment to finally obtain the Ni-Se-C hydrogen evolution electrode.

An electrochemical workstation (Autolab, wangton, switzerland, china ltd) was used to perform electrochemical performance testing on the Ni-Se-C hydrogen evolution electrode material prepared in example 2 in a three-electrode system, with the Ni-Se-C hydrogen evolution electrode as the working electrode, the graphite sheet as the auxiliary electrode, and the SCE as the reference electrode. A hydrogen evolution linear scanning curve is tested by taking a 1mol/L KOH solution as an electrolyte under the conditions that the temperature is 25 ℃ and the scanning speed is 1mV/s, and the curve is shown in figure 3.

Comparative example 1

Comparative example 1 an electrocatalytic hydrogen evolution material was prepared in substantially the same manner as in example 1, except that lysine was not added to deionized water at the time of preparing an aqueous plating solution in step (2).

Comparative example 2

Comparative example 2 an electrocatalytic hydrogen evolution material was prepared in substantially the same manner as in example 1, except that SeO was not added to the deionized water at the time of preparing the aqueous plating solution in the step (2) ₂ 。

Comparative example 3

Comparative example 3 the preparation method of the electrocatalytic hydrogen evolution material was substantially the same as in example 1, except that no NiSO was added to the deionized water when the aqueous plating solution was prepared in step (2) ₄ ·6H ₂ O。

And (3) testing the hydrogen evolution performance of the Ni-Se-C electrode: the electrochemical performance of the Ni-Se-C hydrogen evolution electrode materials prepared in examples 1 to 3 was tested in a three-electrode system using an electrochemical workstation (CHI 600E, beijing, world trade far east scientific instruments ltd), with the Ni-Se-C hydrogen evolution electrode material being a working electrode, the graphite sheet being an auxiliary electrode, and the SCE being a reference electrode. A1 mol/L KOH solution is used as an electrolyte, the temperature is 25 ℃, and the scanning speed is 2 mV/s. Reversible hydrogen electrode and impedance compensation corrections are applied to the electrode potentials, all potentials being obtained according to the following nernst equation: e _RHE ＝E _SCE +0.242+0.059pH-iR (where: i is the current tested and R is the solution impedance). The hydrogen evolution performance test of the electrocatalytic hydrogen evolution materials of comparative examples 1 to 3 was in accordance with the above method.

The electrocatalytic hydrogen evolution materials prepared in examples 1 to 3 and comparative examples 1 to 3 were subjected to a hydrogen evolution performance test, respectively, and the obtained hydrogen evolution overpotentials (mV) were measured as shown in table 1.

TABLE 1 hydrogen evolution overpotential test table for electrocatalytic hydrogen evolution material

Current Density (mA. Cm) ^-2 )	10mA·cm ^-2	50mA·cm ^-2	100mA·cm ^-2
				Example 1	62	188	239
Example 2	90	215	265
				Example 3	115	233	283
Comparative example 1	180	276	354
				Comparative example 2	225	324	401
Comparative example 3	213	311	387

As can be seen from Table 1, the hydrogen evolution potential of the electrodes prepared in examples 1 to 3 gradually increased and the hydrogen evolution performance decreased as the lysine concentration in the plating solution decreased. The main reason is that the carbon content in the coating is reduced along with the reduction of the carbon concentration in the plating solution, the grain size of the coating is increased along with the reduction of the carbon concentration in the plating solution, the active sites of intercrystalline substances/grain boundaries are reduced, and the hydrogen evolution overpotential is improved. The overpotentials for hydrogen evolution of the Ni-Se-C electrodes prepared in examples 1 to 3 were far lower than those of the electrocatalytic hydrogen evolution materials of comparative examples 1 to 3, which indicates that the Ni-Se-C hydrogen evolution electrodes of the present application have excellent hydrogen evolution performance.

Claims

1. A Ni-Se-C hydrogen evolution electrode characterized by: consists of a conductive substrate and a Ni-Se-C plating layer electrodeposited on the surface of the conductive substrate.

2. The Ni-Se-C hydrogen evolution electrode according to claim 1, characterized in that: in the Ni-Se-C coating, the mass percentage of each element is as follows: 40 to 60% of Ni, 40 to 60% of Se and the balance of C.

3. The Ni-Se-C hydrogen evolution electrode according to claim 1, characterized in that: the conductive substrate is a foamed nickel substrate.

4. A method for producing a Ni-Se-C hydrogen evolution electrode according to claim 1, characterized by comprising the steps of:

5. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (1), the nickel source is one or a mixture of several of water-soluble nickel salts; the selenium source is one or a mixture of several of selenium dioxide, sodium selenite and sodium selenate; the carbon source is one or a mixture of arginine, lysine or histidine.

6. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (1), the buffer is boric acid or ammonium chloride.

7. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (1), the conductive agent is one or a mixture of NaCl, liCl or KCl.

8. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (1), in the electroplating aqueous solution, the mass concentration of the nickel source is 20-40 g/L, the mass concentration of the selenium source is 5-20 g/L, the mass concentration of the carbon source is 2-5 g/L, the mass concentration of the buffering agent is 20-60 g/L, and the mass concentration of the conductive agent is 1-10 g/L.

9. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (2), the temperature of the electroplating aqueous solution is 25-50 ℃ in the electrodeposition process.

10. The method for producing a Ni-Se-C hydrogen evolution electrode according to claim 4, characterized in that: in the step (2), the circulating potential in the electrodeposition is-2 to 0.4V; the scanning speed is 2-10 mV/s; the number of cycles is 3-11.