CN112962107B

CN112962107B - Square-meter-level high-activity high-stability nickel electrode, preparation method and application thereof

Info

Publication number: CN112962107B
Application number: CN202110134785.1A
Authority: CN
Inventors: 邹晓新; 李纪红; 陈辉
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2021-12-14
Anticipated expiration: 2041-01-29
Also published as: CN112962107A

Abstract

A square meter nickel electrode with high activity and high stability, a preparation method and application thereof in the aspect of alkaline water cracking oxygen evolution, belonging to the technical field of inorganic functional materials. The method comprises the steps of taking a nickel material as a substrate, taking a deionized water solution containing a ferric iron compound and thiosulfate as a film forming solution, placing the nickel material in the film forming solution at room temperature to form a film for 0.5-10 min in a homogeneous phase, taking out the film, washing the film for multiple times in sequence by deionized water and ethanol, and drying the film at room temperature to obtain the surface-modified nickel electrode with the surface morphology of an amorphous nanosheet. Wherein the ferric iron compound is ferric trichloride hexahydrate or ferric sulfate, and the nickel material is nickel net, nickel sheet or foam nickel. The invention is not limited by a preparation container, does not need external energy input, can react at room temperature, has simple preparation process, short preparation period and high repeatability, and the prepared nickel electrode has higher electrocatalytic oxygen evolution activity and stability under the alkaline condition (6M KOH).

Description

Square-meter-level high-activity high-stability nickel electrode, preparation method and application thereof

Technical Field

The invention belongs to the technical field of inorganic functional materials, and particularly relates to a square-meter-grade high-activity high-stability nickel electrode, a preparation method and application thereof in alkaline water cracking oxygen evolution.

Background

The conversion of the main energy structure from fossil fuels to renewable energy sources (solar, wind, etc.) is a key step to achieve sustainable use of energy without damaging our ecosystem. Electrochemical water splitting is considered a sustainable, clean energy solution. Electrolyzed water consists of two half-reactions: hydrogen Evolution Reaction (HER) at the cathode end and Oxygen Evolution Reaction (OER) at the anode end. Wherein the oxygen evolution reaction is the bottleneck reaction of electrocatalytic water splitting. To accelerate this process, highly active catalysts are required. Currently, the commonly used oxygen evolution catalysts are iridium-based and ruthenium-based catalysts, but they are low in abundance and expensive, which is not favorable for large-scale application. Therefore, there is a need to develop a catalyst which is inexpensive, efficient and stable.

At present, electrocatalytic water oxidation materials are emerging in large numbers, such as transition metal (hydroxy) oxides, sulfides, etc., with NiFe-based (hydroxy) hydroxides being considered the most effective OER catalysts, with many non-noble metal catalysts at 10 mA cm^-2The catalytic activity at current density has exceeded that of noble metal iridium-based and ruthenium-based catalysts. Although great progress is made in the development of non-noble metal OER electro-catalysts, the catalytic life is not satisfactory, and is generally stable for dozens of hours, at most hundreds of hours, and few catalytic materials in thousands of hours are available, so that the requirement of industrial application is difficult to achieve. In addition, most water oxidation catalysts have severe synthesis conditions and are not easy to amplify for synthesis. This makes the practical application of newly developed catalysts in water splitting technology still have great challenges, which greatly limits the progress of the industrial electro-catalytic hydrogen production technology.

Disclosure of Invention

The invention aims to improve the energy conversion efficiency, and provides a square-meter-grade high-activity high-stability nickel electrode, a preparation method and application thereof in the aspect of alkaline water cracking oxygen evolution.

The invention provides a method for preparing a square meter-grade, high-activity and high-stability nickel electrode by rapid surface film forming at room temperature, which is characterized by comprising the following steps of: taking a nickel material as a substrate, taking a deionized water solution containing a ferric iron compound and thiosulfate or taking a deionized water solution containing a ferric iron compound and thioacetamide as a film forming solution, wherein the mass ratio of an iron source to thiosulfate or thioacetamide is 10-1000: 1, placing a nickel material in a film forming solution at room temperature to form a film in a homogeneous phase for 0.5-10 min, taking out, washing with deionized water and ethanol for multiple times in sequence, and drying at room temperature to obtain the surface-modified nickel electrode with the surface morphology of amorphous nanosheets.

In the above method, the ferric compound is ferric trichloride hexahydrate or ferric sulfate.

In the above method, the thiosulfate is one of sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate and lithium thiosulfate.

In the method, the nickel material is nickel mesh, nickel sheet or foam nickel.

In the method, the mass ratio of the ferric iron compound to the thiosulfate in the film-forming liquid is 10-80: 1.

in the method, the concentration of the ferric iron compound in the film-forming solution is 0.5-1.0 g: 10 mL;

in the above method, the film forming reaction is carried out at room temperature without additional energy input.

The invention has the following beneficial effects:

1. the invention quickly synthesizes a series of surface-modified square meter-level) nickel electrodes with amorphous nanosheets at room temperature, is not limited by a preparation container, and is a successful universal preparation method.

2. Compared with the conventional method for preparing ferronickel (hydrothermal method, electrodeposition, electroplating and other methods), the method does not need external energy input, can react at room temperature, has simple preparation process, short preparation period and high repeatability, and greatly reduces the preparation cost.

3. Compared with the powdery catalyst, the nickel electrode integrates the current collector electrode and the catalyst into a whole, and the peeling phenomenon cannot occur in the working environment.

4. The nickel electrode of the invention has higher electrocatalytic oxygen evolution activity and stability under alkaline condition: the current density reaches 10 mA cm^-2The overpotential required is 235 mV, which is stable for over 1200 hours.

Drawings

FIG. 1: an X-ray diffraction (XRD) pattern of the surface-modified nickel mesh electrode (SM-Ni mesh) prepared in example 1.

FIG. 2: example 1 optical photographs of the resulting surface modified nickel mesh electrodes (SM-Ni mesh) of different sizes were prepared. The size of the electrode in the graph (a) is2*5cm²The size of the electrode in graph (b) is 38 x 38 cm²The size of the electrode in graph (c) is 140 × 140 cm²。

FIG. 3: scanning Electron Microscope (SEM) photograph of the surface modified nickel mesh electrode (SM-Ni mesh) prepared in example 1. The scale bar in the figure is 1 μm.

FIG. 4: example 1 a Transmission Electron Microscope (TEM) photograph of the surface-modified nickel mesh electrode (SM-Ni mesh) prepared in example 1. The scale bar of graph (a) is 50nm and the scale bar of graph (b) is 5 nm.

FIG. 5: the surface modified nickel mesh electrode (SM-Ni mesh) Raman spectrum prepared in example 1.

FIG. 6: polarization curve of water splitting oxygen evolution of the surface modified nickel mesh electrode (SM-Ni mesh) prepared in example 1 in alkaline electrolyte (6M KOH). The abscissa is voltage (relative to the reversible hydrogen electrode) and the ordinate is current density, and the data is obtained from polarization curves measured by the electrochemical workstation of shanghai chen CHI650 e.

FIG. 7: stability curve of water-splitting oxygen evolution of the surface-modified nickel mesh electrode (SM-Ni mesh) prepared in example 1 in alkaline electrolyte (6M KOH). The abscissa is time and the ordinate is voltage (relative to the reversible hydrogen electrode), and the data is obtained from chronopotentiometric analysis curves measured by the electrochemical workstation of shanghai chen CHI650 e.

Detailed Description

The present invention is further described with reference to the following examples and drawings, but the scope of the present invention includes, but is not limited to, the following examples, and variations and modifications thereof without departing from the spirit and scope of the present invention are also included in the present invention.

Example 1

Preparing a surface modified nickel screen electrode: 3.5g ferric chloride hexahydrate and 0.1g sodium thiosulfate were dissolved in 50 mL deionized water, and 2 x 5cm²The nickel screen (Ni mesh, 40 mesh) is put into the mixed solution, soaked for 3min and then taken out, washed with deionized water for three times, washed with ethanol for one time and dried at room temperature to obtain the surface modified nickel screen electrode (SM-Ni mesh).

Expanding the volume of the etching solution with the same concentration by 10 times and 70 times, and expanding the volume by 38 x 38 cm²And 140 x 140 cm²And respectively putting the nickel screen (Ni mesh) into etching solution, soaking for 3min, taking out, washing with deionized water for three times, washing with ethanol for one time, and drying at room temperature to prepare the large-area surface modified nickel screen electrode (SM-Ni mesh).

Some structural and performance studies were performed on the materials prepared by the above methods.

FIG. 1 is an XRD spectrum of the obtained SM-Ni mesh, in which the position is assigned to nickel mesh (PDF # 25-2865), indicating that the material is in an amorphous structure;

FIG. 2 is a picture of the obtained SM-Ni mesh, which can be used for preparing a square meter nickel mesh electrode;

FIG. 3 is a Scanning Electron Microscope (SEM) photograph of the obtained SM-Ni mesh, and it can be seen that the surface of the obtained SM-Ni mesh is vertically distributed with nanosheets.

FIG. 4 is a TEM picture of the obtained SM-Ni mesh, and it can be seen from FIG. 4a that the surface of the obtained SM-Ni mesh is composed of nanosheets, and the thickness of the nanosheets is 5-10 nm. Further, fig. 4b shows that the nanosheet has no obvious lattice stripes and is in an amorphous structure.

FIG. 5 is a Raman spectrum of the obtained SM-Ni mesh, 199.7, 321.9, 685.8 cm^-1Classified as Fe-O, 472.3, 553.9 cm^-1Belongs to Ni-O, therefore, the nano-sheet with SM-Ni mesh surface mainly comprises NiFe (OH)_X。

The prepared SM-Ni mesh is subjected to electrocatalytic oxygen evolution performance study in 6M KOH electrolyte under a three-electrode system, wherein a nickel mesh electrode is taken as an anode, and the working area is 1 x 1cm²The platinum wire is used as a counter electrode, and the mercury oxidation mercury electrode is used as a reference electrode. Here, it is pointed out that: the main battery of the electrochemical work station is an external power supply for electrocatalytic oxygen evolution work; the potentials obtained by using mercury oxide as a reference electrode are all converted into reversible hydrogen electrode potentials in a property diagram.

FIG. 6 is a diagram of the electrocatalytic oxygen evolution property of the material in 6M KOH electrolyte, with the current density reaching 10 mA cm^-2When (corresponding to an abscissa of 1.465V),the overpotential required for SM-Ni mesh was 235 mV, which was reduced by 83 mV compared to Ni mesh (318 mV, corresponding to 1.548V in the abscissa).

FIG. 7 shows that the current density of the material in 6M KOH electrolyte is 10 mA cm^-2The constant current stability curve can be stable for more than 1200 hours, which shows that the material has high catalytic activity and excellent catalytic stability under alkaline conditions.

Example 2

The surface modified nickel mesh electrode can be prepared by changing the soaking time to 1 min, 5min and 10min as in the example 1. In 6M KOH electrolyte, the current density reaches 10 mA cm^-2The overpotential required is 248 mV, 235 mV and 230 mV, respectively.

Example 3

The same as example 1, the mass of sodium thiosulfate was changed to 0.05g and 0.15g, and the surface-modified nickel mesh electrode was prepared by soaking for 3 min. In 6M KOH electrolyte, the current density reaches 10 mA cm^-2The overpotential required is 245 mV and 232 mV, respectively.

Example 4

In the same manner as in example 1, the surface-modified nickel mesh electrode was prepared by changing sodium thiosulfate to thioacetamide (0.1 g by mass) and soaking for 3 min. In 6M KOH electrolyte, the current density reaches 10 mA cm^-2The desired overpotential is 225 mV.

Example 5

The surface modified nickel sheet electrode was prepared by changing the nickel mesh to a nickel sheet (thickness 0.3 mm) and soaking for 3min, as in example 1. In 6M KOH electrolyte, the current density reaches 10 mA cm^-2The desired overpotential is 282 mV.

Example 6

The nickel mesh was changed to nickel foam (thickness 0.3 mm) and soaked for 3min to prepare a surface-modified nickel sheet electrode, as in example 1. In 6M KOH electrolyte, the current density reaches 10 mA cm^-2The desired overpotential is 245 mV.

Example 7

Similar to example 1, the surface modified nickel mesh electrode can be prepared by changing ferric trichloride hexahydrate into ferric sulfate (3.5 g for mass) and soaking for 3min, and the performance is similar to that of example 1.

Claims

1. A method for preparing a square meter nickel electrode with high activity and high stability is characterized by comprising the following steps: taking a nickel material as a substrate, taking a deionized water solution containing a ferric iron compound and thiosulfate or taking a deionized water solution containing a ferric iron compound and thioacetamide as a film forming solution, wherein the mass ratio of an iron source to thiosulfate or thioacetamide is 10-1000: 1, placing a nickel material in a film forming solution at room temperature to form a homogeneous film for 0.5-10 min, taking out, sequentially washing with deionized water and ethanol for multiple times, and drying at room temperature to obtain a surface-modified nickel electrode with an amorphous nanosheet surface appearance; wherein the ferric iron compound is ferric trichloride hexahydrate or ferric sulfate, and the nickel material is nickel net, nickel sheet or foam nickel.

2. The method for preparing a square meter, high activity and high stability nickel electrode according to claim 1, wherein: the thiosulfate is one of sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate or lithium thiosulfate.

3. The method for preparing a square meter, high activity and high stability nickel electrode according to claim 1, wherein: the mass ratio of the ferric iron compound to the thiosulfate in the film forming liquid is 10-80: 1.

4. the method for preparing a square meter, high activity and high stability nickel electrode according to claim 1, wherein: the concentration of the ferric iron compound in the film-forming solution is 0.5-1.0 g: 10 mL.

5. The utility model provides a square meter level, high activity, high stability's nickel electrode which characterized in that: is prepared by the method of any one of claims 1 to 4.

6. The use of the square meter, high activity, high stability nickel electrode of claim 5 for alkaline water-splitting oxygen evolution.