A self-supported electrocatalyst composed of cobalt and cerium supported on porous carbonized wood

Abstract

The application provides a self-supporting electrocatalyst of cobalt-cerium loaded porous carbonized wood, and belongs to the technical field of porous catalysts. Wood chips are subjected to delignification treatment, heat treatment and acid treatment to obtain carbonized wood, in a three-electrode system, the carbonized wood is used as a working electrode, cobalt nitrate and cerium nitrate are used to form an electrolyte, and a self-supporting electrocatalyst of Co (OH) 2-CeO2 loaded porous carbonized wood is obtained through electrodeposition. The electrocatalyst prepared by the application not only has low cost, is green and environment-friendly, and the electrode can be self-supported, but also has high and stable electrocatalytic performance, and the application of wood in the field of electrocatalysis is expanded.

Description

Technical Field

[0001] This application relates to a self-supporting electrocatalyst made of cobalt and cerium supported on porous carbonized wood, belonging to the field of porous catalyst technology. Background Technology

[0002] With the increasing environmental problems caused by the combustion of fossil fuels, there is an urgent need to develop renewable and clean energy sources. The electrochemical oxygen evolution reaction (OER) plays a crucial role in various energy conversion and storage technologies. The anodic oxygen evolution reaction (OER) involves a four-electron transfer process, which is slow and energy-intensive, requiring a high overpotential to drive the reaction. Furthermore, the noble metal catalysts primarily used in the OER, such as RuO2 and IrO2, are limited in application due to their high cost and low reserves. Therefore, developing low-cost, stable, and efficient OER electrocatalysts is of great significance.

[0003] To improve the activity of OER electrocatalysts, constructing electrocatalysts with synergistic effects among different species is a common approach. Cerium dioxide is an important rare earth metal oxide, and CeO2 possesses Ce... 4+ and Ce 3+ Controllable changes between states, abundant oxygen vacancies, unique redox properties, high oxygen mobility, and corrosion resistance have led to their widespread application in electrocatalysts in recent years. On the other hand, cobalt hydroxide (Co(OH)₂) is widely considered one of the best-performing OER catalysts. The synergistic effect of both further promotes electron transfer. However, the issue of unsustainable support remains.

[0004] Currently, commercial carbon supports for catalysts, such as carbon paper, graphite plates, and carbon cloth, suffer from drawbacks such as high cost and non-degradability. Furthermore, electrocatalysts require adhesion to the support for testing. Biomass carbon materials are widely available and abundant, and have been applied in energy production, pharmaceuticals, food packaging, and electrochemistry. Wood, in particular, is abundant on Earth and is biodegradable. Wood is easily carbonized, and after carbonization, it becomes conductive. Its excellent mechanical properties make it suitable for use as an independent electrode. Carbonized wood, as an independent electrode, allows for direct deposition of electrocatalysts onto the electrode via electrodeposition, a simple and easy process. Wood itself has a porous structure, which is retained after carbonization. The vertically arranged channels facilitate electrolyte penetration and gas release, increasing the OER reaction rate. Summary of the Invention

[0005] In view of this, this application provides a self-supporting electrocatalyst supported on porous carbonized wood, which uses lignin-free carbonized wood as a carrier for electrodeposition of Co(OH)2-CeO2. This not only has low cost and is environmentally friendly, but also has a self-supporting electrode and high efficiency and stable electrocatalytic performance, thus expanding the application of wood in the field of electrocatalysis.

[0006] Specifically, this application is implemented through the following scheme:

[0007] A self-supported electrocatalyst composed of cobalt and cerium supported on porous carbonized wood, the preparation steps of which are as follows:

[0008] Step one: Wood chips undergo lignin removal, heat treatment, and acid treatment to obtain carbonized wood.

[0009] Step 2: In the three-electrode system, carbonized wood, platinum sheet and Hg / HgO electrode are used as working electrode, counter electrode and reference electrode respectively. Cobalt nitrate and cerium nitrate are used as electrolyte. A self-supporting electrocatalyst of Co(OH)2-CeO2 supported by porous carbonized wood is obtained by electrodeposition.

[0010] The preparation method of this self-supporting electrocatalyst mainly includes the following steps: wood chips are subjected to lignin removal, heat treatment, and acid treatment to obtain carbonized wood, which is used as a self-supporting electrode; in a three-electrode system, the carbonized wood serves as the working electrode, and the electrolyte consists of cobalt nitrate and cerium nitrate. A Co(OH)₂-CeO₂ self-supporting electrocatalyst supported on porous carbonized wood is obtained by electrodeposition. The electrocatalyst prepared in this invention uses lignin-removed carbonized wood as a self-supporting electrode, with Co(OH)₂ and CeO₂ loaded on the surface and inner walls of the pores of the wood. The three-dimensional porous structure inherent in the wood is retained even after heat treatment. The lignin removal method further expands the pore size, increases the specific surface area, and exposes more electrocatalytic active sites. Furthermore, the synergistic effect of Co(OH)₂ and CeO₂, which play the main catalytic role, can improve reaction activity, enhance electronic conductivity, and expand reaction pathways, thereby promoting catalytic activity and stability.

[0011] In step one:

[0012] The lignin treatment method is as follows: Prepare a 3-5% NaClO2 solution, adjust the pH of the solution to 4-5, immerse the wood chips in the solution, and heat in a water bath at 90-100℃ for 1-6 hours to remove lignin. After the reaction is complete, cool to room temperature, ultrasonically clean the wood chips repeatedly with deionized water and ethanol, and dry to obtain lignin-free wood chips.

[0013] The heat treatment refers to: placing the lignin-removed wood chips in a tube furnace, first heat-treating them at 400-600℃ in an argon atmosphere for 1-4 hours, then raising the temperature to 800-1000℃ for another 1-4 hours, and finally cooling them to room temperature to obtain carbonized wood. More preferably, the lignin-removed wood chips are first heat-treated at 500℃ for 1 hour, then raised to 900℃ for 2 hours.

[0014] The acid treatment refers to immersing the heat-treated wood chips in 65% nitric acid and ultrasonically treating them for 0.5 to 2 hours, then ultrasonically cleaning them with deionized water and ethanol and drying them to obtain hydrophilic carbonized wood.

[0015] In step two:

[0016] The electrolyte consists of 0~0.1M cobalt nitrate and 0~0.1M cerium nitrate.

[0017] The molar ratio of cobalt nitrate to cerium nitrate is 1~9:1~9.

[0018] During electrodeposition, carbonized wood first forms at 10~20 mA cm⁻¹ -2 Anodizing for 300-800 seconds, to reduce NO3 - Intercalation, then at -10 to -20 mA cm -2 Cathodic deposition lasts 300–2000 s. More preferably, carbonized wood is first deposited at 20 mA cm⁻¹. -2 Anodizing, then at -20mA cm -2 Cathode deposition.

[0019] The aforementioned self-supported electrocatalyst is directly used as a self-supported electrode for the oxygen evolution reaction (OER). This electrocatalyst uses carbonized wood as the self-supporting electrode, with Co(OH)₂-CeO₂ supported on the surface and within the pore walls of the carbonized wood. Using carbonized wood as an independent electrode and loading the electrocatalyst via electrodeposition solves the problems of non-degradability of traditional supports and difficulty in loading electrocatalysts. Furthermore, the porous structure of the wood itself facilitates electrolyte penetration and gas release, increasing the OER reaction rate. In addition, the synergistic effect of Co(OH)₂ and CeO₂ further promotes electron transfer, thereby improving reaction kinetics.

[0020] Compared with the prior art, the beneficial effects of this application can be summarized as follows:

[0021] (1) Compared with traditional carbon carriers, wood is widely available, low in cost and environmentally friendly. Moreover, wood has certain mechanical properties, and a self-supporting carbon carrier can be obtained through simple heat treatment, which can be used directly as an electrode.

[0022] (2) Wood itself has a three-dimensional porous structure, and this structural feature can still be maintained after heat treatment. The above-mentioned lignin removal treatment further expands the pore size and increases the specific surface area, exposing more electrocatalytic active sites, thereby greatly improving the electrocatalytic activity.

[0023] (3) Co(OH)2 and CeO2 loaded on wood play the main catalytic role. Their synergistic effect can improve the reaction activity, enhance electronic conductivity, and expand the reaction pathway, thereby promoting catalytic activity and stability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a scanning electron microscope image of the self-supporting electrocatalyst of Example 1;

[0026] Figure 2 This is a scanning electron microscope image of carbonized wood that has not undergone lignin removal treatment according to the present invention;

[0027] Figure 3 The diagram shows the pore size and pore wall thickness of the wood before and after lignin removal according to the present invention.

[0028] Figure 4 Water contact angle diagrams for wood chips, lignin-free wood chips, carbonized wood, and acid-treated carbonized wood of the present invention;

[0029] Figure 5 The XRD patterns are of the electrocatalysts of Example 1 and Comparative Examples 3 and 4.

[0030] Figure 6 The graph shows a comparison of linear sweep voltammetry tests of the oxygen evolution reaction of the self-supported electrocatalysts in Examples 1-4.

[0031] Figure 7 This is a comparison graph of the linear sweep voltammetry test results of the oxygen evolution reaction of the electrocatalysts in Example 1 and Comparative Examples 1-4.

[0032] Figure 8 This is a stability graph of the self-supporting electrocatalyst in Example 1. Detailed Implementation

[0033] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the technical solutions in the embodiments of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit the technical solutions of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0034] Example 1

[0035] This application provides a self-supporting electrocatalyst composed of cobalt and cerium supported on porous carbonized wood, and its preparation process is as follows:

[0036] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0037] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0038] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0039] (4) Electrodeposition was performed using a traditional three-electrode system, with carbonized wood, platinum sheet, and Hg / HgO electrode used as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.07 M Co(NO3)2 and 0.03 M Ce(NO3)3. During the electrodeposition process, the carbonized wood was first subjected to an electrodeposition at 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 1200 s. Then it was washed with deionized water and ethanol and dried to obtain a Co(OH)2-CeO2 self-supporting electrocatalyst supported on carbonized wood.

[0040] Example 2

[0041] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0042] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0043] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0044] (4) Electrodeposition was performed using a traditional three-electrode system, with carbonized wood, platinum sheet, and Hg / HgO electrode used as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.07 M Co(NO3)2 and 0.03 M Ce(NO3)3. During the electrodeposition process, the carbonized wood was first subjected to an electrodeposition at 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 300 s. Then it was washed with deionized water and ethanol and dried to obtain a Co(OH)2-CeO2 self-supporting electrocatalyst supported on carbonized wood.

[0045] Example 3

[0046] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0047] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0048] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0049] (4) Electrodeposition was performed using a traditional three-electrode system, with carbonized wood, platinum sheet, and Hg / HgO electrode used as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.07 M Co(NO3)2 and 0.03 M Ce(NO3)3. During the electrodeposition process, the carbonized wood was first subjected to an electrodeposition at 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 600 s. Then it was washed with deionized water and ethanol and dried to obtain a Co(OH)2-CeO2 self-supporting electrocatalyst supported on carbonized wood.

[0050] Example 4

[0051] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0052] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0053] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0054] (4) Electrodeposition was performed using a traditional three-electrode system, with carbonized wood, platinum sheet, and Hg / HgO electrode used as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.07 M Co(NO3)2 and 0.03 M Ce(NO3)3. During the electrodeposition process, the carbonized wood was first subjected to an electrodeposition at 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 1800 s. Then it was washed with deionized water and ethanol and dried to obtain a Co(OH)2-CeO2 self-supporting electrocatalyst supported on carbonized wood.

[0055] Comparative Example 1

[0056] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0057] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0058] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0059] Comparative Example 2

[0060] In this comparative example, the commercial ruthenium oxide catalyst from Shanghai Myriel Chemical Technology Co., Ltd. was used as the ruthenium oxide electrocatalyst.

[0061] Comparative Example 3

[0062] The processing procedure for this comparative example is as follows:

[0063] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0064] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0065] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0066] (4) A traditional three-electrode system was used for electrodeposition, with carbonized wood, platinum sheet, and Hg / HgO electrode serving as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.1 M Ce(NO3)3. During the electrodeposition process, the carbonized wood was first subjected to an electrode depth of 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 1200 s. Then it was washed with deionized water and ethanol and dried to obtain a CeO2 self-supporting electrocatalyst supported on carbonized wood.

[0067] Comparative Example 4

[0068] The processing procedure for this comparative example is as follows:

[0069] (1) Cut the paulownia wood block into wood chips of 2cm×4cm×3mm. Prepare a 5% NaClO2 solution, adjust the pH of the solution to 4.6 with acetic acid, and then soak the wood chips in the solution and heat in a water bath at 90℃ for 2h to remove lignin. After the reaction is completed, cool to room temperature, ultrasonically clean the wood chips several times with deionized water and ethanol, and dry them to obtain lignin-free wood chips.

[0070] (2) The dried wood chips are placed in a tube furnace and heat-treated in an argon atmosphere at 500°C for 1 hour, and then heated to 900°C for 2 hours. After cooling to room temperature, carbonized wood is obtained.

[0071] (3) Soak the carbonized wood in 65% nitric acid and sonicate for 0.5 h, then sonicate clean with deionized water and ethanol and dry to obtain hydrophilic carbonized wood.

[0072] (4) A traditional three-electrode system was used for electrodeposition, with carbonized wood, a platinum sheet, and an Hg / HgO electrode serving as the working electrode, counter electrode, and reference electrode, respectively. The electrolyte consisted of 0.1 M Co(NO3)2. During the electrodeposition process, the carbonized wood was first subjected to an electrode depth of 20 mA cm⁻¹. -2 Anodizing for 600 seconds reduces NO3 - Intercalation, then at -20mA cm -2 The cathode was deposited for 1200 s. Then it was washed with deionized water and ethanol and dried to obtain a Co(OH)2 self-supporting electrocatalyst supported on carbonized wood.

[0073] The products prepared in the above cases were tested, and the results are as follows:

[0074] Depend on Figure 1 and Figure 2 The scanning electron microscope (SEM) images shown demonstrate that, compared to carbonized wood without lignin removal treatment, Example 1 exhibits a three-dimensional porous structure, which facilitates electrolyte penetration and gas release. Furthermore, it is clearly observed that the electrocatalyst is uniformly deposited on the outer and inner pore walls of the wood, exposing more active sites and promoting electron transfer, thereby increasing the catalytic reaction rate.

[0075] Combination Figure 3 It can be seen that the lignin removal treatment increases the pore size and thins the pore walls of the wood. Taking Example 1 as an example, after the lignin removal treatment, the pore size d of the wood chips with a pore size d = 12.38 ± 0.26 μm and a wall thickness d = 1.59 ± 0.08 μm increased to 16.15 ± 0.25 μm and the wall thickness d decreased to 1.10 ± 0.01 μm. This morphological change further expands the electron transport channels, promotes electron transfer, and accelerates the reaction rate.

[0076] Depend on Figure 4 The water contact angle diagram shows that carbonized wood exhibits significant hydrophobicity compared to untreated wood chips, but becomes hydrophilic after acid treatment. Taking Example 1 as an example, the water contact angle (CA) of untreated wood chips is approximately 69.98°, that of lignin-free wood chips is approximately 35.43°, that of carbonized wood is approximately 115.99°, and that of acid-treated carbonized wood is approximately 28.57°. When carbonized wood is used as an electrode, its hydrophilicity promotes electrolyte penetration and is also more conducive to NO3- absorption. - During the intercalation and subsequent deposition process, the electrocatalyst is firmly loaded onto the carbonized wood.

[0077] Figure 5 The XRD patterns shown demonstrate that the product obtained in Example 1 was successfully loaded with both Co(OH)2 and CeO2, while Comparative Example 3 was successfully loaded with only CeO2, and Comparative Example 4 was successfully loaded with Co(OH)2.

[0078] Figure 6 The linear voltammetric scan results show that the longer the deposition time, the more cobalt-cerium catalyst is loaded on the wood chip. Example 1, with a deposition time of 1200s, corresponds to the product with the highest current density and the lowest over-potential, meaning its oxygen evolution performance is better than that of Examples 2-4. Examples 2 and 3, with cathode deposition times of 300s and 600s respectively, have shorter deposition times, resulting in lower loading and poorer OER performance. Example 4, with a deposition time of 1800s, has a larger catalyst loading, but its performance is still worse than that of Example 1. This is because the excessively long cathode deposition time leads to an excessive loading, which does not necessarily improve OER performance. Therefore, it is best to control the cathode deposition time between 300 and 2000s. Under the cathode conditions of Example 1, the deposition time should be kept around 1200s.

[0079] Figure 7 The linear voltammetric scan results show that: Comparative Example 1 is untreated carbonized wood. Comparing Example 1 and Comparative Example 1, it can be seen that the performance of carbonized wood without catalyst support is lower, which also confirms that the two catalysts were successfully supported in this case. Meanwhile, the product of Example 1, which is supported by both catalysts Co(OH)2 and CeO2, has the highest current density and the lowest overpotential. Its oxygen evolution performance and improvement in reaction activity significantly exceed the simple combined effect of Comparative Examples 3 and 4, which also confirms that the synergistic effect of Co(OH)2 and CeO2 significantly improves the reaction activity in this case. Furthermore, the self-supporting carbonized wood substrate provides active sites to further promote reaction activity, which is superior to RuO2 (Comparative Example 2), the most commercially available electrocatalyst with good OER performance, and can replace commercial electrocatalysts.

[0080] Figure 8 The stability graph shown demonstrates that after 100 hours of testing, the voltage of the product obtained in Example 1 remained essentially unchanged, exhibiting excellent stability.

[0081] The above-described embodiments are merely illustrative of several feasible implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. Given the numerous embodiments of the present invention and the vast amount of experimental data for each embodiment, it is not suitable to list and describe them all here. However, the content to be verified and the final conclusions obtained in each embodiment are similar. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. All equivalent implementations or changes that do not depart from the scope of the present invention should be included in the technology of the present invention.

Claims

1. A self-supporting electrocatalyst of cobalt cerium supported by porous carbonized wood, characterized in that, The preparation steps of the self-supporting electrocatalyst are as follows: Step one, the wood chips are subjected to delignification treatment, heat treatment and acid treatment to obtain carbonized wood, Step two, in a three-electrode system, the carbonized wood, platinum sheet and Hg / HgO electrode are used as the working electrode, the counter electrode and the reference electrode respectively, the cobalt nitrate and cerium nitrate constitute the electrolyte, and the self-supporting electrocatalyst of Co(OH)2-CeO2 supported by the porous carbonized wood is obtained through electrodeposition, During the electrodeposition process, the carbonized wood is first subjected to 10-20 mA cm -2 Anodization for 300-800 s, resulting in NO3 - Intercalation, followed by -10 - -20 mA cm -2 Cathodic deposition for 300-2000 s.

2. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. In step one, the delignification treatment method is as follows: a 3-5% NaClO2 solution is configured, the pH value of the solution is adjusted to 4-5, the wood chips are soaked in the solution, and the delignification treatment is performed by heating in a water bath at 90-100℃ for 1-6h.

3. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. In step one, the heat treatment refers to that the wood chips after delignification treatment are first subjected to heat treatment at 400-600℃ under argon atmosphere for 1-4h, and then subjected to heat treatment at 800-1000℃.

4. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. The wood chips after delignification treatment are first subjected to heat treatment at 500℃ for 1h, and then subjected to heat treatment at 900℃ for 2h.

5. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. In step one, the acid treatment refers to that the wood chips after heat treatment are soaked in 65% nitric acid and subjected to ultrasonic treatment for 0.5-2h.

6. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. In step two, the electrolyte is composed of 0-0.1M cobalt nitrate and 0-0.1M cerium nitrate.

7. The self-supported electrocatalyst of cobalt and cerium supported on porous carbonized wood according to claim 1 or 6, characterized by the fact that: The molar ratio of cobalt nitrate to cerium nitrate is 1-9:1-9.

8. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. Carbonized wood was first at 20 mA cm -2 Anodically treated, then at -20 mA cm -2 Cathodically deposited.

9. The self-supported electrocatalyst of claim 1, wherein the porous carbonized wood is loaded with cobalt and cerium. The self-supporting electrocatalyst is directly used as a self-supporting electrode for oxygen evolution reaction.

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