A method for preparing an indium-modified multilayered carbon-based catalyst

Abstract

This invention discloses a method for preparing an indium-modified multilayered carbon-based catalyst, comprising the following steps: Step S1. Reacting Zn(NO3)2·6H2O solution with dimethylimidazole solution to obtain ZIF-8; Step S2. Mixing and reacting the ZIF-8, indium salt, and solvent to obtain indium-doped ZIF-8 powder; Step S3. Calcining the indium-doped ZIF-8 powder to obtain the indium-modified multilayered carbon-based catalyst. The indium-modified multilayered carbon-based catalyst prepared by this invention exhibits a multilayered structure with an uneven surface. Under the action of the indium-modified multilayered carbon-based catalyst, the single-selective electrocatalytic reduction of carbon dioxide to carbon monoxide is achieved, which is expected to be applied to the efficient conversion of carbon dioxide gas.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide electrocatalysis, and particularly to a method for preparing an indium-modified multilayered carbon-based catalyst. Background Technology

[0002] With industrial development, the consumption of fossil fuels has increased dramatically, producing excessive carbon dioxide gas, causing the greenhouse effect and a series of environmental problems. To address this issue, researchers have explored several methods to convert carbon dioxide, including thermocatalysis, photocatalysis, and electrocatalysis. Compared to other reduction methods, electrocatalysis has simpler equipment and milder reaction conditions, making it more popular among scientists.

[0003] Electroreduction of carbon dioxide typically yields both single-carbon and multi-carbon products. Single-carbon products include carbon monoxide and formic acid, while multi-carbon products include ethylene, ethanol, and propanol. However, the electroreduction of carbon dioxide still faces several challenges. First, the high thermodynamic stability of the CO2 molecule necessitates overcoming a significant energy barrier for the activation of the C=O double bond. Second, the resulting products from carbon dioxide electroreduction are complex in composition. Third, in an aqueous electrolyte, competing reactions (hydrogen evolution reaction) readily occur, reducing product formation. Finally, the low solubility of CO2 in water limits the rate of the CO2 reduction reaction. These factors contribute to low catalytic activity, low Faraday efficiency, and poor stability in the electrocatalytic CO2 reduction reaction. Therefore, preparing highly selective, highly active, and highly stable catalysts is crucial for achieving efficient CO2 reduction (RR). Summary of the Invention

[0004] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of the present invention is to provide a method for preparing an indium-modified multilayered carbon-based catalyst. When the indium-modified multilayered carbon-based catalyst of the present invention is applied to the electroreduction reaction of carbon dioxide, the product obtained is mainly carbon monoxide, and the selectivity is high.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing an indium-modified multilayered carbon-based catalyst includes the following steps:

[0007] Step S1. Reaction of Zn(NO3)2·6H2O solution with dimethylimidazole solution yields ZIF-8;

[0008] Step S2. Mix and react the ZIF-8, indium salt and solvent to obtain indium-doped ZIF-8 powder;

[0009] Step S3. Calcining the indium-doped ZIF-8 powder yields an indium-modified multilayered carbon-based catalyst.

[0010] Preferably, in step S1, the concentration ratio of Zn(NO3)2·6H2O to dimethylimidazole is 1:1.

[0011] Preferably, in step S1, the solvent of the Zn(NO3)2·6H2O solution is methanol; the solvent of the dimethylimidazole solution is methanol.

[0012] Preferably, in step S1, the reaction temperature is 25–30°C, and the reaction time is 10–13 hours.

[0013] Preferably, in step S2, the indium salt is InCl3·4H2O.

[0014] Preferably, in step S2, the mass ratio of the indium salt to ZIF-8 is (0.3 to 1.7):1.

[0015] Preferably, in step S2, the reaction temperature is 25–30°C, and the reaction time is 1–3 hours.

[0016] Preferably, in step S3, the calcination temperature is 800–1000°C, and the calcination time is 1–3 hours.

[0017] Another object of the present invention is to provide an indium-modified multilayered carbon-based catalyst, wherein the indium-modified multilayered carbon-based catalyst is prepared by the same method as the indium-modified multilayered carbon-based catalyst.

[0018] Another object of the present invention is to provide the application of the indium-modified multilayered carbon-based catalyst in the reduction of carbon dioxide.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) This invention provides an indium-modified multilayered carbon-based catalyst. Compared with the prior art, the indium-modified multilayered carbon-based catalyst disclosed in this invention has a specific structure and morphology. The catalyst exhibits a multilayered structure with an uneven surface and no obvious clusters or nanoparticles are formed. Due to its large specific surface area, this material can expose more active sites, thereby promoting the efficient reduction of carbon dioxide.

[0021] (2) The present invention obtains a cheap and readily available carbon material through a dual solvent method and high-temperature pyrolysis.

[0022] (3) The indium-modified multilayered carbon-based catalyst provided by the present invention can carry out carbon dioxide electroreduction reaction in a conventional H-type electrolytic cell, and the main product generated is carbon monoxide, and the Faraday efficiency of carbon monoxide can reach 90%.

[0023] (4) The preparation method provided by the present invention is relatively simple, the product has high selectivity, and has certain application prospects. Attached Figure Description

[0024] Figure 1 The image shows a scanning electron microscope image of the indium-modified multilayered carbon-based catalyst prepared in Example 2.

[0025] Figure 2 The image shows the X-ray diffraction pattern of the indium-modified multilayered carbon-based catalyst prepared in Example 2.

[0026] Figure 3 The image shows a linear voltammetric scan of the indium-modified multilayered carbon-based catalyst prepared in Example 2.

[0027] Figure 4 The Faraday efficiency curves of the indium-modified multilayered carbon-based catalyst prepared in Example 2 for producing carbon monoxide under different standard hydrogen electrodes during the electrocatalytic reduction of carbon dioxide are shown. Detailed Implementation

[0028] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0029] Example 1

[0030] This embodiment provides an indium-modified multilayered carbon-based catalyst, the specific process of which is as follows:

[0031] Preparation of ZIF-8:

[0032] Mix 0.1M and 100mL of Zn(NO3)2·6H2O in methanol until homogeneous, then mix 0.1M and 100mL of dimethylimidazole in methanol until homogeneous; then quickly pour the 0.1M and 100mL of dimethylimidazole in methanol into the 0.1M and 100mL of Zn(NO3)2·6H2O in methanol; stir at room temperature for 10–13 h; centrifuge and wash several times with methanol; dry under vacuum at 60℃ for 12 h to obtain white ZIF-8 powder.

[0033] Preparation process of indium-doped ZIF-8:

[0034] 300 mg of ZIF-8 powder was weighed and dispersed in 50 mL of n-hexane. A methanol solution of 0.30–0.70 mmol InCl3·4H2O was slowly added dropwise. The mixture was magnetically stirred at room temperature for 1–3 h. The powder was washed several times by centrifugation with methanol and then dried under vacuum at 60 °C for 12 h to obtain indium-doped ZIF-8 powder.

[0035] Preparation process of indium-modified multilayered carbon-based catalyst:

[0036] A certain amount of indium-doped ZIF-8 powder was placed in a tube furnace, which was filled with argon (Ar) gas. Before heating, the gas was passed through for 30 min. Under the argon (Ar) atmosphere, the temperature was raised to 1000℃ and held for 1–3 h at a heating rate of 5℃ / min. Then, the temperature was slowly lowered to room temperature at a rate of 5℃ / min to obtain the final indium-modified multilayered carbon-based catalyst.

[0037] Example 2

[0038] This embodiment provides an indium-modified multilayered carbon-based catalyst, the specific process of which is as follows:

[0039] Preparation of ZIF-8:

[0040] Mix 0.1M and 100mL of Zn(NO3)2·6H2O in methanol until homogeneous, then mix 0.1M and 100mL of dimethylimidazole in methanol until homogeneous; then quickly pour the 0.1M and 100mL of dimethylimidazole in methanol into the 0.1M and 100mL of Zn(NO3)2·6H2O in methanol; stir at room temperature for 10–13 h; centrifuge and wash several times with methanol; dry under vacuum at 60℃ for 12 h to obtain white ZIF-8 powder.

[0041] Preparation process of indium-doped ZIF-8:

[0042] 300 mg of ZIF-8 powder was weighed and dispersed in 50 mL of n-hexane. A methanol solution of 0.80–1.20 mmol InCl3·4H2O was slowly added dropwise. The mixture was magnetically stirred at room temperature for 1–3 h. The powder was then washed several times by centrifugation with methanol and dried under vacuum at 60 °C for 12 h to obtain indium-doped ZIF-8 powder.

[0043] Preparation process of indium-modified multilayered carbon-based catalyst:

[0044] A certain amount of indium-doped ZIF-8 powder was placed in a tube furnace, which was filled with argon (Ar) gas. Before heating, the gas was passed through for 30 min. Under the argon (Ar) atmosphere, the temperature was raised to 1000℃ and held for 1–3 h at a heating rate of 5℃ / min. Then, the temperature was slowly lowered to room temperature at a rate of 5℃ / min to obtain the final indium-modified multilayered carbon-based catalyst.

[0045] Example 3

[0046] This embodiment provides an indium-modified multilayered carbon-based catalyst, the specific process of which is as follows:

[0047] Preparation of ZIF-8:

[0048] Mix 0.1M and 100mL of Zn(NO3)2·6H2O in methanol until homogeneous, then mix 0.1M and 100mL of dimethylimidazole in methanol until homogeneous; then quickly pour the 0.1M and 100mL of dimethylimidazole in methanol into the 0.1M and 100mL of Zn(NO3)2·6H2O in methanol; stir at room temperature for 10–13 h; centrifuge and wash several times with methanol; dry under vacuum at 60℃ for 12 h to obtain white ZIF-8 powder.

[0049] Preparation process of indium-doped ZIF-8:

[0050] 300 mg of ZIF-8 powder was weighed and dispersed in 50 mL of n-hexane. A methanol solution of 1.30–1.70 mmol InCl3·4H2O was slowly added dropwise. The mixture was magnetically stirred at room temperature for 1–3 h. The powder was washed several times by centrifugation with methanol and then dried under vacuum at 60 °C for 12 h to obtain indium-doped ZIF-8 powder.

[0051] Preparation process of indium-modified multilayered carbon-based catalyst:

[0052] A certain amount of indium-doped ZIF-8 powder was placed in a tube furnace, which was filled with argon (Ar) gas. Before heating, the gas was passed through for 30 min. Under the argon (Ar) atmosphere, the temperature was raised to 1000℃ and held for 1–3 h at a heating rate of 5℃ / min. Then, the temperature was slowly lowered to room temperature at a rate of 5℃ / min to obtain the final indium-modified multilayered carbon-based catalyst.

[0053] Experimental Example 1

[0054] This experimental example characterizes the indium-modified multilayered carbon-based catalyst prepared in Example 2 of the present invention.

[0055] See Figure 1 and Figure 2 As shown, Figure 1 This is a scanning electron microscope image of the indium-modified multilayered carbon-based catalyst prepared in Example 2 of the present invention; Figure 2 This is an X-ray diffraction image of the indium-modified multilayered carbon-based catalyst prepared in Example 2 of the present invention.

[0056] like Figure 1 As shown, due to the high-temperature pyrolysis process, the catalyst exhibits a multi-layered structure with an uneven surface, and no obvious clusters or nanoparticles are formed; for example... Figure 2 As shown, there are no obvious peaks of particles in the X-ray diffraction image.

[0057] Experimental Example 2

[0058] This experimental example tests the catalytic performance of an indium-modified multilayered carbon-based catalyst:

[0059] The catalytic performance of the indium-modified multilayered carbon-based catalyst prepared in Example 2 of this invention was tested for the electroreduction reaction of carbon dioxide.

[0060] Carbon cloth loaded with the indium-modified multilayered carbon-based catalyst obtained in Example 2 of this invention was used as the working electrode, a platinum sheet as the counter electrode, and a silver / silver chloride electrode as the reference electrode. The electrolyte was a 0.5 mol / L potassium bicarbonate solution. The carbon dioxide electroreduction performance was tested in an H-type electrolytic cell. The test adopted a constant voltage method, with the applied voltage range being -0.5V to -1.0V vs. RHE. The gaseous products of the reaction were detected by gas chromatography, and the liquid products were examined by ion chromatography. The coulombic amount corresponding to the product concentration was calculated, and the selectivity, activity, and other data of the catalyst were obtained based on the total coulombic amount recorded by the electrochemical workstation.

[0061] See Figure 3 , Figure 3 This is a linear voltammetric scan of the indium-modified multilayered carbon-based catalyst prepared in Example 2 of the present invention.

[0062] See Figure 4 , Figure 4 The Faraday efficiency curves of carbon monoxide production by the indium-modified multilayered carbon-based catalyst prepared in Example 2 of this invention under different standard hydrogen electrodes during the electrocatalytic reduction of carbon dioxide are shown.

[0063] Figure 4 The figure shows a schematic diagram of the product distribution of electrocatalytic carbon dioxide reduction under different current densities in Example 2. As shown, at each test potential, the gaseous product of the electrocatalytic reduction of carbon dioxide by the indium-modified multilayered carbon-based catalyst obtained in Example 2 is carbon monoxide, accompanied by a small amount of hydrogen gas. Furthermore, it was found that the obtained indium-modified multilayered carbon-based catalyst exhibits high selectivity for catalytic conversion to carbon monoxide.

[0064] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An indium-modified multiple-layered carbon-based catalyst, characterized by: Prepared by a method including the following steps: Step S1. Zn(NO3)2·6H2O solution reacts with dimethylimidazole solution to obtain ZIF-8; the solvent of Zn(NO3)2·6H2O solution is methanol; the solvent of dimethylimidazole solution is methanol. Step S2. The ZIF-8, indium salt, and solvent are mixed and reacted to obtain indium-doped ZIF-8 powder; the mass ratio of indium salt to ZIF-8 is (0.3~1.7):1; the solvent is n-hexane; Step S3. Calcining the indium-doped ZIF-8 powder yields an indium-modified multilayered carbon-based catalyst. The indium-modified multilayered carbon-based catalyst is used for the electrocatalytic reduction of carbon dioxide to carbon monoxide.

2. The indium-modified multi-layered carbon-based catalyst of claim 1, wherein: In step S1, the concentration ratio of Zn(NO3)2·6H2O to dimethylimidazole is 1:

1.

3. The indium-modified multi-layered carbon-based catalyst of claim 1, wherein: In step S1, the reaction temperature is 25~30℃; the reaction time is 10~13 hours.

4. The indium-modified multilayered carbon-based catalyst according to claim 1, characterized in that: In step S2, the indium salt is InCl3·4H2O.

5. The indium-modified multilayered carbon-based catalyst according to claim 1, characterized in that: In step S2, the reaction temperature is 25~30℃; the reaction time is 1~3 hours.

6. The indium-modified multilayered carbon-based catalyst according to claim 1, characterized in that: In step S3, the calcination temperature is 800~1000 ℃; the calcination time is 1~3 hours.

7. The application of an indium-modified multilayered carbon-based catalyst as described in any one of claims 1 to 6 in the electrocatalytic reduction of carbon dioxide.

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