Preparation method and use of photosensitive and cobalt-doped nickel selenide cathode for water electrolysis

Abstract

A preparation method and use of a photosensitive, cobalt-doped nickel selenide cathode for water electrolysis is defined. The preparation method includes the following steps: preparing a cobalt-contai

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of hydrogen production by water electrolysis, in particular to a preparation method and use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis. BACKGROUND

[0002] With the proposal of a "carbon peaking and carbon neutrality" strategic goal, the research on renewable clean energy has become a goal of the vast number of scientific and technological workers in China. Hydrogen, whose specific energy is much higher than that of most hydrocarbons, is a widely concerned zero-carbon emission fuel. However, currently hydrogen in China is still mainly produced through fossil fuels, and the proportion of hydrogen produced by water electrolysis is still at an extremely low level. Therefore, it is necessary to develop an efficient and sustainable technology to reduce the cost of hydrogen production by water electrolysis, so as to meet requirements of the "carbon peaking and carbon neutrality" strategic goal.

[0003] For a water electrolysis device, a total voltage that needs to be provided externally to complete water splitting is E= 1.23 V + the overpotential of the cathode + the overpotential of the anode + the potential required to overcome other resistances. Therefore, improving the catalytic performance of electrode materials and reducing their overpotentials is an effective means to reduce the required operating voltage of water electrolysis devices. In addition, it can be determined that the electricity required to overcome the overpotential of a catalyst only accounts for a part of the total electricity consumption, while a fixed energy barrier of 1.23 V required to achieve the water splitting accounts for the other major part. Therefore, it is an important way to reduce the power consumption of water electrolysis by compensating the 1.23 V potential required for water splitting using a renewable energy source. SUMMARY

[0004] Based on problems existing in the background, the present disclosure proposes a preparation method and use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis. The preparation method includes the following steps:

[0005] SI: dissolving cobalt nitrate in N,N-dimethylformamide to obtain a cobalt-containing precursor solution;

[0006] S2: completely immersing a nickel foam mesh in the precursor solution for 2 sec to 4 sec, taking out, and air-drying naturally to obtain a precursor solution-attached nickel foam mesh; and

[0007] S3: placing the precursor solution-attached nickel foam mesh in a middle position of a temperature control zone of a horizontal tubular furnace, placing a selenium powder upstream position of the nickel foam mesh, conducting a reaction at 450°C to 550°C for 55 min to 65 min to obtain cobalt-doped nickel selenide, and directly connecting the cobalt-doped nickel selenide to a water electrolysis device as a cathode for water electrolysis.

[0008] Preferably, in step SI, the precursor solution has the cobalt nitrate at a concentration of 0.4 g / mL.

[0009] Preferably, in step S2, the nickel foam mesh is completely immersed in the precursor solution for 3 sec and then taken out.

[0010] Preferably, in step S3, the selenium powder is spread 15 cm from the upstream position of the nickel foam mesh, the reaction is conducted at 500°C for 60 min to obtain the cobalt-doped nickel selenide, and the cobalt-doped nickel selenide is directly connected to the water electrolysis device as the cathode for water electrolysis.

[0011] Preferably, the present disclosure further provides use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis prepared by the preparation method, where the cobalt-doped nickel selenide cathode for water electrolysis is applied to an water electrolysis device; the water electrolysis device includes a cathode for water electrolysis, a graphite paper-based counter electrode, a reference electrode, and an electrolyte; the reference electrode is a Hg / HgO reference electrode; and the electrolyte is a potassium hydroxide solution with a pH value of 14. Through the photosensitive and cobalt-doped nickel selenide cathode for water electrolysis, a hydrogen production performance by water electrolysis of the water electrolysis device under light illumination is improved, thereby reducing the operating cost of the water electrolysis device.

[0012] Compared with the prior art, the present disclosure has the following beneficial effects: 1) In the present disclosure, the nickel selenide has a desirable electrocatalytic hydrogen evolution performance, and part of the nickel selenide also has certain semiconductor characteristics; for semiconductor materials, the photoelectric effect can affect the amount of charge on the surface of a material as well as the potential inside. Therefore, on the basis of water electrolysis, the photoelectric effect of nickel selenide semiconductor is stimulated by light illumination to improve the electrical properties of a surface of the material, and generate a self-generating effect, thereby reducing an external voltage required for the water electrolysis. This enables compensation for a 1.23 V potential required for water splitting by the renewable solar energy, thus reducing electricity consumption for water electrolysis.

[0013] 2) In the present disclosure, the cathode for water electrolysis is applied to a hydrogen production device based on water electrolysis, showing obvious performance advantages; through the effect of solar energy, the water electrolysis efficiency has been significantly improved compared with the traditional cathodes for electrolysis water.

[0014] 3) In the present disclosure, the preparation method is simple and easy to operate. The preparation method can obtain a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis, and a water electrolysis device prepared by the cathode for water electrolysis does not include any rare and precious metals such as platinum and iridium, thereby saving the cost. Meanwhile, due to the photosensitivity of cobalt-doped nickel selenide, using the solar energy can reduce a power consumption of the water electrolysis device and enhance the absorption and utilization of visible light. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 shows a scanning electron microscopy (SEM) image of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis; and

[0016] FIG. 2 shows a polarization curve of the photosensitive and cobalt-doped nickel selenide cathode for water electrolysis. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The technical solutions of the embodiments of the present disclosure are clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are merely a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0018] The present disclosure proposes a preparation method and use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis. The preparation method includes the following steps:

[0019] SI: dissolving cobalt nitrate in N,N-dimethylformamide to obtain a cobalt-containing precursor solution;

[0020] S2: completely immersing a nickel foam mesh in the precursor solution for 2 sec to 4 sec, taking out, and air-drying naturally to obtain a precursor solution-attached nickel foam mesh; and

[0021] S3: placing the precursor solution-attached nickel foam mesh in a middle position of a temperature control zone of a horizontal tubular furnace, placing a selenium powder upstream position of the nickel foam mesh, conducting a reaction at 450°C to 550°C for 55 min to 65 min to obtain cobalt-doped nickel selenide, and directly connecting the cobalt-doped nickel selenide to a water electrolysis device as a cathode for water electrolysis.

[0022] Further, in step SI, the precursor solution has the cobalt nitrate at a concentration of 0.4 g / mL.

[0023] Further, in step S2, the nickel foam mesh is completely immersed in the precursor solution for 3 sec and then taken out.

[0024] Further, in step S3, the selenium powder is spread 15 cm from the upstream position of the nickel foam mesh, the reaction is conducted at 500°C for 60 min to obtain the cobalt-doped nickel selenide, and the cobalt-doped nickel selenide is directly connected to the water electrolysis device as the cathode for water electrolysis. The SEM image in FIG. 1 shows that the photosensitive and cobalt-doped nickel selenide cathode for water electrolysis has a void structure, and a large number of wrinkles on a surface thereof enhance a specific surface area of the electrode.

[0025] Further, the present disclosure further provides use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis prepared by the preparation method, where the cobalt-doped nickel selenide cathode for water electrolysis is applied to an water electrolysis device; the water electrolysis device includes a cathode for water electrolysis, a graphite paper-based counter electrode, a reference electrode, and an electrolyte; the reference electrode is a Hg / HgO reference electrode; and the electrolyte is a potassium hydroxide solution with a pH value of 14. As shown in FIG. 2, in the dark, the cobalt-doped nickel selenide cathode for water electrolysis has a hydrogen production current density of 50 mA / cm2 under an overpotential of 140 mV. After the introduction of light illumination, under the same overpotential of 140 mV, the cobalt-doped nickel selenide cathode for water electrolysis has a hydrogen production current density of 63 mA / cm2. Through the photosensitive and cobalt-doped nickel selenide cathode for water electrolysis, a hydrogen production performance by water electrolysis of the water electrolysis device under light illumination is improved, thereby reducing the operating cost of the water electrolysis device.

[0026] The above described are merely preferred implementations of the present disclosure. It should be pointed out that the preferred implementations should not be construed as a limitation to the present disclosure, and the protection scope of the present disclosure should be subject to the claims of the present disclosure. Those of ordinary skill in the art may make several improvements and modifications without departing from the spirit and scope of the present disclosure, but the improvements and modifications should fall within the protection scope of the present disclosure.

Claims

1. A preparation method of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis, comprising the following steps:SI: dissolving cobalt nitrate in N,N-dimethylformamide to obtain a cobalt-containing precursor solution;S2: completely immersing a nickel foam mesh in the precursor solution for 2 sec to 4 sec, taking out with tweezers, and air-drying naturally at a room temperature for not less than 2 h to obtain a precursor solution-attached nickel foam mesh; andS3: placing the precursor solution-attached nickel foam mesh in a middle position of a temperature control zone of a horizontal tubular furnace, spreading a selenium powder on an upstream position of the nickel foam mesh, conducting a reaction at 450°C to 550°C for 55 min to 65 min to obtain cobalt-doped nickel selenide, and directly connecting the cobalt-doped nickel selenide to a water electrolysis device as a cathode for water electrolysis.

2. The preparation method of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis according to claim 1, wherein in step SI, the precursor solution has the cobalt nitrate at a concentration of 0.4 g / mL.

3. The preparation method of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis according to claim 1, wherein in step S2, the nickel foam mesh is completely immersed in the precursor solution for 3 sec and then taken out.

4. The preparation method of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis according to claim 1, wherein in step S3, the selenium powder is spread 15 cm from the upstream position of the nickel foam mesh, the reaction is conducted at 500°C for 60 min to obtain the cobalt-doped nickel selenide, and the cobalt-doped nickel selenide is directly connected to the water electrolysis device as the cathode for water electrolysis.

5. Use of a photosensitive and cobalt-doped nickel selenide cathode for water electrolysis prepared by the preparation method according to any one of claims 1 to 4, wherein the cobalt-doped nickel selenide cathode for water electrolysis is applied to an water electrolysis device; the water electrolysis device comprises a cathode for water electrolysis, a graphite paper-based counter electrode, a reference electrode, and an electrolyte; the reference electrode is a Hg / HgO reference electrode; and the electrolyte is a potassium hydroxide solution with a pHvalue of 14.

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