CN114934291B - A partitioned electrode of an alkaline water electrolyzer based on non-uniform electrodeposition and its preparation method - Google Patents

Abstract

The invention relates to a partitioned electrode of an alkaline water electrolytic cell based on non-uniform electrodeposition and a preparation method thereof. The electrode includes an electrode base and an electrode terminal for providing current input to the electrode base; the two ends of the electrode base correspond to The inlet side and the outlet side of the electrolytic cell, a catalyst layer is deposited on the surface of the electrode substrate, and the catalyst density in the catalyst layer decreases along the gradient from the inlet side to the outlet side of the electrolytic cell. Compared with the prior art, the invention has the advantage of high hydrogen production efficiency.

Description

A kind of partition electrode of alkaline water electrolyzer based on non-uniform electrodeposition and preparation method

technical field

The invention relates to the technical field of hydrogen production by alkaline water electrolysis, in particular to a partitioned electrode of an alkaline water electrolyzer based on non-uniform electrodeposition and a preparation method thereof.

Background technique

Hydrogen production by electrolysis of water is one of the most commonly used hydrogen production technologies at present. Among them, the hydrogen production technology by electrolysis of alkaline water is relatively mature and has been commercialized. With the increase of market demand, the size and production capacity of alkaline water electrolysis cells continue to increase. In the future, the diameter of a single set of electrolytic cell will exceed 2m, and the production capacity will exceed 1500Nm3/h. The electrode is the core component of the electrolyzer. The increase in size and capacity puts forward higher requirements on the electrode. It is necessary to increase the electrode area and load high-performance catalysts on the basis of the existing nickel mesh electrode.

The enlargement of the electrolytic cell will inevitably lead to uneven temperature distribution in the radial direction of the electrolytic cell. The temperature measured near the lye inlet is lower and the temperature near the outlet is higher. The inlet temperature is low, the reaction activity is low, and the hydrogen production efficiency is low, while the outlet temperature is high, so the hydrogen production rate is too fast, resulting in air resistance. Therefore, different positions have different requirements for the electrode reaction process.

In view of the above problems, combined with the reaction characteristics inside the electrolyte, it is urgent to design the radial distribution of electrodes used in large-area electrolyzers to meet the reaction needs of different positions in large-scale electrolyzers, thereby improving the hydrogen production efficiency of electrolyzers.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned defects in the prior art and provide a highly efficient hydrogen production based on non-uniform electrodeposition alkaline water electrolyzer partition electrode and preparation method to cater to the reaction of different positions of large electrolyzer electrodes need.

The purpose of the present invention can be achieved through the following technical solutions:

According to the first aspect of the present invention, a kind of alkaline water electrolyzer partition electrode based on non-uniform electrodeposition is provided, comprising an electrode base and an electrode terminal for providing current input to the electrode base; the two ends of the electrode base are respectively Corresponding to the inlet side and outlet side of the electrolytic cell, a catalyst layer is deposited on the surface of the electrode substrate, and the catalyst density in the catalyst layer decreases gradually along the direction from the inlet side to the outlet side of the electrolytic cell.

Preferably, the electrode substrate is a metal braided mesh substrate, and its material includes nickel base, iron base or alloy.

Preferably, the shapes of the electrode base include circle and square.

Preferably, the density of the catalyst on the electrode base decreases isogradiently.

Preferably, the number of the electrode terminals is at least one.

According to the second aspect of the present invention, there is provided a preparation method for the partition electrode of the above-mentioned alkaline water electrolyzer based on non-uniform electrodeposition. Current, the electrode substrate is gradually immersed in the electrolyte for N times, and electrodeposition is carried out, and a gradient distribution electrode is obtained after the end.

Preferably, the N is 1-50.

Preferably, the N is 3-20.

Preferably, the electrodeposition time of each step ranges from 1 min to 24 h.

Preferably, the electrodeposition time of each step ranges from 5 minutes to 2 hours.

Compared with the prior art, the present invention has the following advantages:

The invention adopts electrode structure design and gradient distribution catalyst electrode preparation, and the inlet test catalyst density is high. On the one hand, the ohmic resistance can be increased to increase the heat production at the inlet, and the temperature of the electrolyte can be increased. On the other hand, increasing the catalyst density can increase the reaction active sites and improve Hydrogen production efficiency; as the temperature of the electrolyte increases, the catalyst density is reduced to avoid air lock caused by too fast a hydrogen production rate; the lower catalyst density at the outlet can significantly reduce the hydrogen production efficiency and heat production, avoid the occurrence of air lock, and effectively improve electrolysis The comprehensive hydrogen production efficiency of the cell improves the comprehensive hydrogen production efficiency of the electrode, which meets the temperature characteristics of the inlet and outlet of the electrolytic cell and the electrode reaction requirements, and can essentially improve the hydrogen production efficiency of the electrode.

Description of drawings

Fig. 1 is the partition electrode schematic diagram of alkaline water electrolyzer based on heterogeneous electrodeposition of the present invention;

Fig. 2 is the schematic diagram of electrodeposition process in embodiment 2; Wherein, Fig. 2 a is the schematic diagram of X1 time electrodeposition electrode structure; Fig. 2 b is X1+X2 time electrodeposition electrode structure schematic diagram; Fig. 2 c is X1+X2+X3 time electrodeposition diagram Schematic diagram of the electrodeposition structure; Figure 2d is a schematic diagram of the electrodeposition electrode structure at X1+X2+X3+X4 time;

Among them, 1-electrode substrate, 2-electrode terminal.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

Example 1

This embodiment provides a partition electrode for alkaline water electrolyzer based on non-uniform electrodeposition, including an electrode base 1 and an electrode terminal 2 for providing current input to the electrode base 1; the two ends of the electrode base 1 are respectively Corresponding to the inlet side and outlet side of the electrolytic cell, a catalyst layer is deposited on the surface of the electrode substrate 1, and the catalyst density in the catalyst layer decreases gradually along the direction from the inlet side to the outlet side of the electrolytic cell.

The electrode base 1 is a metal braided mesh base, which can be a uniformly distributed metal wire base or extend into a non-uniform structure. Its material can be nickel base, iron base and other different metals or metal alloy materials.

The shape of the electrode base 1 includes circle, square and any other geometric shapes.

The number of the electrode terminals 2 is at least one.

Next, a method embodiment of the present invention is given, a preparation method for the above-mentioned partitioned electrode of an alkaline water electrolyzer based on non-uniform electrodeposition, the method includes: hanging the electrode base 1 vertically, using the electrode terminal The electrode base 1 is input with current, and the electrode base is gradually immersed in the electrolyte for N times in one minute, for electrodeposition, and a gradient distribution electrode is obtained after the end. Among them, the electrodeposition time at the lower end of the electrode is long, and the catalyst density is high, which gradually decreases step by step upward.

Wherein, N is 1-50, especially 3-20; the electrodeposition time range of each step is 1min-24h, especially 5min-2h.

Example 2

The nickel mesh uniformly woven with nickel metal wires is used as the electrode base 1, and the catalyst is deposited on the surface of the electrode base 1, and the current is input from the top of the electrode base 1 through the electrode terminal 2, wherein the number of the electrode terminal 2 is 1. Immerse 1/4 of the electrode base in the electrolyte containing nickel and iron, and deposit nickel-iron alloy on the surface of the nickel mesh by electrodeposition. The deposition time is 20min-2h; 1/2 is immersed in the electrolyte containing nickel and iron, and the nickel-iron alloy is deposited on the surface of the nickel mesh by electrodeposition. The deposition time is 20min-2h; after the deposition is completed, the electrode substrate is further down until 3/4 of the electrode substrate is immersed In the electrolyte containing nickel and iron, the nickel-iron alloy is deposited on the surface of the nickel mesh by electrodeposition, and the deposition time is 20min-2h; after the deposition is completed, the electrode substrate is further lowered until the electrode substrate is completely immersed in the electrolyte containing nickel and iron In the process, the nickel-iron alloy is deposited on the surface of the nickel mesh by electrodeposition, and the deposition time is 20min-2h, and the electrodes with gradient distribution are finally obtained.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can easily think of various equivalents within the technical scope disclosed in the present invention. Modifications or replacements shall all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. An alkaline water electrolysis cell partition electrode based on non-uniform electrodeposition, which is characterized by comprising an electrode substrate (1) and an electrode binding post (2) for providing current input to the electrode substrate (1); the two ends of the electrode matrix (1) respectively correspond to the inlet side and the outlet side of the electrolytic tank, a catalyst layer is deposited on the surface of the electrode matrix (1), and the catalyst density in the catalyst layer is reduced in a gradient manner along the direction from the inlet side to the outlet side of the electrolytic tank.

2. The alkaline water electrolysis cell partition electrode based on non-uniform electrodeposition according to claim 1, wherein the electrode substrate (1) is a metal woven mesh substrate, and the material of the electrode substrate comprises nickel base, iron base or alloy.

3. The alkaline water cell partition electrode based on non-uniform electrodeposition according to claim 1, wherein the shape of the electrode base (1) comprises a circular shape and a square shape.

4. The alkaline water cell partition electrode based on non-uniform electrodeposition according to claim 1, wherein the catalyst density on the electrode substrate (1) is reduced with an equal gradient.

5. The alkaline water cell partition electrode based on non-uniform electrodeposition according to claim 1, wherein the number of electrode studs (2) is at least 1.

6. A method for preparing a partitioned electrode for a non-uniform electrodeposition-based alkaline water electrolysis cell according to claim 1, comprising: and (3) hanging the electrode matrix (1) vertically, inputting current to the electrode matrix (1) by using the electrode binding post (2), immersing the electrode matrix (1) into electrolyte step by step for N times, and carrying out electrodeposition to obtain the gradient distribution electrode after the completion of electrodeposition.

7. The method of claim 6, wherein N is 1 to 50.

8. The method of claim 7, wherein N is 3-20.

9. The method of claim 6, wherein the electrodeposition time of each step is in the range of 1min to 24h.

10. The method of claim 9, wherein the electrodeposition time of each step is in the range of 5min to 2h.