A sea urchin-like Fe2O3@CuSiO3 catalyst and its preparation method

Abstract

This invention discloses a sea urchin-like Fe2O3@CuSiO3 catalyst and its preparation method. First, a precursor Fe2O3@SiO2 is prepared, and then the sea urchin-like Fe2O3@CuSiO3 catalyst is prepared via a hydrothermal method. Compared to the traditional calcination method, this invention uses a hydrothermal method to grow the sample, which simplifies sample preparation, provides milder reaction conditions, lowers the requirements for experimental equipment, and utilizes widely available and abundant raw materials, resulting in high economic benefits. The prepared Fe2O3@CuSiO3 possesses a unique sea urchin-like structure, which effectively increases the specific surface area of ​​the material, allowing for more thorough contact between the material and the electrolyte, while also providing abundant reactive sites.

Description

Technical Field

[0001] This invention relates to the field of inorganic electrochemical technology, and more specifically to a sea urchin-shaped Fe2O3@CuSiO3 catalyst and its preparation method. Background Technology

[0002] With the rapid industrial and economic development of the past few centuries, the excessive consumption of fossil fuels has caused a series of problems. Among these problems, the increasing accumulation of CO2 emissions into the atmosphere has been a major concern. Excessively high CO2 concentrations have become a primary factor contributing to global warming, polar ice melting, and ocean acidification. Therefore, effectively addressing the energy crisis and environmental pollution has become a global challenge.

[0003] CO2 capture, storage, or conversion technologies can transform CO2 into high-value-added fuels, facilitating the establishment of carbon-neutral systems. Various C1 and C2 products can be prepared on the surface of metallic Cu catalysts. Strong Cu-O-Si interfacial sites promote the hydrogenation of *CO to *COH and inhibit catalyst remodeling, playing a crucial role in the electrochemical reduction of CO2. Fe2O3@CuSiO3, with its strong Cu-O-Si interface, is an ideal catalytic material. It possesses stable Cu... 2+ The role of species in regulating the microenvironment and mediating the adsorption of intermediates plays an important role in the field of CO2 electrochemical reduction. Summary of the Invention

[0004] In view of this, the present invention provides a sea urchin-shaped Fe2O3@CuSiO3 catalyst and its preparation method, wherein Fe2O3@CuSiO3 powder is obtained by hydrothermal method, thereby improving the efficiency of CO2 electrochemical reduction.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a sea urchin-shaped Fe2O3@CuSiO3 catalyst includes the following steps: (1) Disperse Fe2O3 ultrasonically in a mixed solution of ethanol and deionized water, then add tetraethyl orthosilicate and ammonia, stir for a certain time to obtain a suspension, centrifuge at 7000r for 5min to obtain a precipitate, wash with deionized water and ethanol alternately to obtain red powder Fe2O3@SiO2, and dry for later use. (2) After mixing CuCl2·2H2O and NH4Cl powder, add deionized water to dissolve them, then add Fe2O3@SiO2 powder obtained in step (1), and ultrasonically disperse to obtain a uniform suspension; (3) Add ammonia to the suspension obtained in step (2), stir until the mixture is uniform, put it into a polytetrafluoroethylene liner for hydrothermal reaction, cool to room temperature after the reaction is completed, take out the suspension, centrifuge at 7000r for 10min to obtain the precipitate, and wash with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3.

[0006] Preferably, in step (1), the volume ratio of ethanol to deionized water is 6:1, the volume ratio of ammonia to tetraethyl orthosilicate is 10:1, and the molar ratio of tetraethyl orthosilicate to ferric oxide is 2:1.

[0007] Preferably, the stirring time in step (1) is 17-18 hours.

[0008] Preferably, in step (2), the mass ratio of Fe2O3@SiO2 to NH4Cl is 3:50, and the molar ratio of CuCl2·2H2O to NH4Cl is 7:50.

[0009] Preferably, in steps (1)-(2), the ultrasonic power is 180w and the dispersion time is 30min-120min.

[0010] Preferably, the volume ratio of ammonia in step (3) to deionized water in step (2) is 1:20.

[0011] Preferably, the hydrothermal reaction temperature in step (3) is 140-150℃ and the time is 19-21h.

[0012] The present invention also provides a sea urchin-shaped Fe2O3@CuSiO3 catalyst prepared by the method described above.

[0013] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a sea urchin-like Fe2O3@CuSiO3 catalyst and its preparation method, which has the following beneficial effects: Compared to the traditional calcination method, this invention uses a hydrothermal method to grow samples, which is simple to prepare, has relatively mild reaction conditions, and requires less experimental equipment. Fe2O3@CuSiO3 samples are simple to prepare, the required raw materials are widely available and abundant, and the economic benefits are high. Fe2O3@CuSiO3 has a unique sea urchin-like structure, which can effectively increase the specific surface area of ​​the material, allowing for more thorough contact between the material and the electrolyte, while also providing abundant reactive sites; Copper silicate (CuSiO3) can stabilize Cu in a reducing reaction environment. 2+ Substances that facilitate the formation of two-carbon products; By changing the amounts of TEOS and CuCl2·2H2O, the tip curvature can be controlled, thereby regulating the proportion of C products. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0015] Figure 1 (a), (b), (c), and (d) are schematic diagrams of Fe2O3@CuSiO3 under a transmission electron microscope, corresponding to Comparative Example 1, Comparative Example 2, Example 1, and Comparative Example 3, respectively. Figure 2 Comparison of X-ray diffraction (XRD) patterns of Fe2O3@CuSiO3 in Comparative Examples 1, 2, 1, and 3 of this invention; Figure 3 This is a Faraday efficiency diagram of Fe2O3@CuSiO3 prepared in Comparative Example 1 of this invention; Figure 4 This is the Faraday efficiency diagram of Fe2O3@CuSiO3 prepared in Comparative Example 2 of this invention; Figure 5 This is a Faraday efficiency diagram of Fe2O3@CuSiO3 prepared in Example 1 of this invention; Figure 6 This is a Faraday efficiency diagram of Fe2O3@CuSiO3 prepared in Comparative Example 3 of this invention. Detailed Implementation

[0016] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] Comparative Example 1 The preparation method of sea urchin-shaped Fe2O3@CuSiO3 catalyst includes the following steps: (1) Fe2O3 was ultrasonically treated at 180W for 2h to disperse it in a mixed solution of 90mL ethanol and 15mL deionized water. Then, 50uL tetraethyl orthosilicate (TEOS) and 2mL ammonia were added. After magnetic stirring for 17h, a suspension was obtained. After centrifugation at 7000r for 5 minutes, a precipitate was obtained. After washing with deionized water and ethanol alternately, red powder Fe2O3@SiO2 was obtained and dried for later use. (2) Mix 0.03g CuCl2·2H2O and 0.265g NH4Cl powder and add 20mL deionized water to dissolve. Then add 0.0175g Fe2O3@SiO2 powder obtained in step (1) and sonicate at 180W for 30min to obtain a uniform suspension. (3) Add 1 mL of ammonia water to the suspension obtained in step (2), stir magnetically until the mixture is uniform, put it into a 25 mL polytetrafluoroethylene inner liner, put it into a drying oven, and react at 140℃ for 20 h. After the reaction is completed, cool to room temperature, take out the suspension, centrifuge at 7000 r for 10 minutes to obtain the precipitate, wash it with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3, and label the obtained sample as Fe2O3@CuSiO3-1.

[0018] Comparative Example 2 The preparation method of sea urchin-shaped Fe2O3@CuSiO3 catalyst includes the following steps: (1) Fe2O3 was ultrasonically treated at 180W for 2h to disperse it in a mixed solution of 90mL ethanol and 15mL deionized water. Then, 100uL tetraethyl orthosilicate (TEOS) and 2mL ammonia were added. After magnetic stirring for 17h, a suspension was obtained. After centrifugation at 7000r for 5 minutes, a precipitate was obtained. After washing with deionized water and ethanol alternately, red powder Fe2O3@SiO2 was obtained and dried for later use. (2) Mix 0.06g CuCl2·2H2O and 0.265g NH4Cl powder and add 20mL deionized water to dissolve. Then add 0.0175g Fe2O3@SiO2 powder obtained in step (1) and sonicate at 180W for 30min to obtain a uniform suspension. (3) Add 1 mL of ammonia water to the suspension obtained in step (2), stir magnetically until the mixture is uniform, put it into a 25 mL polytetrafluoroethylene inner liner, put it into a forced-air drying oven, and react at 140℃ for 20 h. After the reaction is completed, cool to room temperature, take out the suspension, centrifuge at 7000 r for 10 minutes to obtain the precipitate, wash it with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3, and label the obtained sample as Fe2O3@CuSiO3-2.

[0019] Example 1 The preparation method of sea urchin-shaped Fe2O3@CuSiO3 catalyst includes the following steps: (1) Fe2O3 was ultrasonically treated at 180W for 2h to disperse it in a mixed solution of 90mL ethanol and 15mL deionized water. Then, 200uL tetraethyl orthosilicate (TEOS) and 2mL ammonia were added. After magnetic stirring for 17h, a suspension was obtained. After centrifugation at 7000r for 5 minutes, a precipitate was obtained. After washing with deionized water and ethanol alternately, red powder Fe2O3@SiO2 was obtained and dried for later use. (2) Mix 0.12g CuCl2·2H2O and 0.265g NH4Cl powder and add 20mL deionized water to dissolve. Then add 0.0175g Fe2O3@SiO2 powder obtained in step (1) and sonicate at 180W for 30min to obtain a uniform suspension. (3) Add 1 mL of ammonia water to the suspension obtained in step (2), stir magnetically until the mixture is uniform, put it into a 25 mL polytetrafluoroethylene inner liner, put it into a drying oven, and react at 140℃ for 20 h. After the reaction is completed, cool to room temperature, take out the suspension, centrifuge at 7000 r for 10 minutes to obtain the precipitate, wash it with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3, and label the obtained sample as Fe2O3@CuSiO3-3.

[0020] Comparative Example 3 The preparation method of sea urchin-shaped Fe2O3@CuSiO3 catalyst includes the following steps: (1) Fe2O3 was ultrasonically treated at 180W for 2h to disperse it in a mixed solution of 90mL ethanol and 15mL deionized water. Then, 300uL tetraethyl orthosilicate (TEOS) and 2mL ammonia were added. After magnetic stirring for 17h, a suspension was obtained. After centrifugation at 7000r for 5 minutes, a precipitate was obtained. After washing with deionized water and ethanol alternately, red powder Fe2O3@SiO2 was obtained and dried for later use. (2) Mix 0.18g CuCl2·2H2O and 0.265g NH4Cl powder and add 20mL deionized water to dissolve. Then add 0.0175g Fe2O3@SiO2 powder obtained in step (1) and sonicate at 180W for 30min to obtain a uniform suspension. (3) Add 1 mL of ammonia water to the suspension obtained in step (2), stir magnetically until the mixture is uniform, put it into a 25 mL polytetrafluoroethylene inner liner, put it into a drying oven, and react at 140℃ for 20 h. After the reaction is completed, cool to room temperature, take out the suspension, centrifuge at 7000 r for 10 minutes to obtain the precipitate, wash with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3, and label the obtained sample as Fe2O3@CuSiO3-4.

[0021] Experimental Example The electrochemical performance of Fe2O3@CuSiO3 was tested using a gas diffusion electrolytic cell. First, 10 mg of the sample was mixed with 800 μL of isopropanol and 200 μL of deionized water, then ultrasonicated for 30 min using a 180 W ultrasonic cleaner to obtain a homogeneous suspension. Finally, the suspension was drop-coated onto hydrophobic carbon paper as the working electrode; a platinum mesh electrode served as the counter electrode; and an Ag / AgCl electrode served as the reference electrode. The electrolyte was a 1 M potassium hydroxide solution (pH = 13.7). The overpotential test range was -1.1 to -1.6 (vs. Ag / AgCl).

[0022] Figure 1 Images (a), (b), (c), and (d) are transmission electron microscope (TEM) schematic diagrams of the Fe2O3@CuSiO3 catalysts obtained in Comparative Examples 1, 2, 1, and 3 of this invention, respectively. TEM results show that the Fe2O3@CuSiO3 catalysts obtained under all four conditions exhibit a urchin-like core-shell structure. With increasing proportions of TEOS and CuCl2·2H2O in the mixed solvent, the apex angle of the surface spikes on Fe2O3@CuSiO3 gradually decreases, reaching its minimum in Example 1, and then gradually increases. The spike density gradually increases, reaching its maximum in Example 1, and then gradually decreases.

[0023] Figure 2 This is a comparison of the X-ray diffraction (XRD) patterns of Fe2O3@CuSiO3 prepared in Example 1 and Comparative Examples 1-3 under different solvent ratios. For Fe2O3@CuSiO3 in Comparative Example 1, after removing the characteristic peaks of Fe2O3, the remaining diffraction peaks are all consistent with hexagonal CuSiO3 (PDF#98-0198).

[0024] Figure 3 Figures 4, 5, and 6 show the Faradaic efficiency diagrams measured under the same conditions in Comparative Examples 1, 2, 1, and 3. These diagrams characterize the energy utilization efficiency of the catalysts and can be used to evaluate catalyst performance in the CO2 electrocatalytic reaction. For Fe2O3@CuSiO3-1 and Fe2O3@CuSiO3-2 in Comparative Examples 1 and 2, the Faradaic efficiency of the carbon products is approximately 40%; for Fe2O3@CuSiO3-3 in Example 1, the Faradaic efficiency of the carbon products is approximately 80%; and for Fe2O3@CuSiO3-4 in Comparative Example 3, the Faradaic efficiency of the carbon products is approximately 60%.

[0025] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a sea urchin-shaped Fe2O3@CuSiO3 catalyst, characterized in that, Includes the following steps: (1) Disperse Fe2O3 ultrasonically in a mixed solution of ethanol and deionized water, then add tetraethyl orthosilicate and ammonia, stir for a certain time to obtain a suspension, centrifuge at 7000r for 5min to obtain a precipitate, wash with deionized water and ethanol alternately to obtain red powder Fe2O3@SiO2, and dry for later use. (2) After mixing CuCl2·2H2O and NH4Cl powder, add deionized water to dissolve them, then add Fe2O3@SiO2 powder obtained in step (1), and ultrasonically disperse to obtain a uniform suspension; (3) Add ammonia to the suspension obtained in step (2), stir until it is evenly mixed, put it into a polytetrafluoroethylene liner for hydrothermal reaction, cool to room temperature after the reaction is completed, take out the suspension, centrifuge at 7000r for 10min to obtain the precipitate, wash with deionized water and ethanol alternately to obtain Fe2O3@CuSiO3. The Fe2O3@CuSiO3 is used in the electrochemical reduction reaction of CO2 to produce C product.

2. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, In step (1), the volume ratio of ethanol to deionized water is 6:1, the volume ratio of ammonia to tetraethyl orthosilicate is 10:1, and the molar ratio of tetraethyl orthosilicate to ferric oxide is 2:

1.

3. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, The stirring time in step (1) is 17-18 hours.

4. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, In step (2), the mass ratio of Fe2O3@SiO2 to NH4Cl is 3:50, and the molar ratio of CuCl2·2H2O to NH4Cl is 7:

50.

5. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, In steps (1)-(2), the ultrasonic power is 180W and the dispersion time is 30min-120min.

6. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, In step (3), the volume ratio of ammonia water to deionized water in step (2) is 1:

20.

7. The method for preparing the urchin-like Fe2O3@CuSiO3 catalyst according to claim 1, characterized in that, In step (3), the hydrothermal reaction temperature is 140-150℃ and the time is 19-21h.

8. A sea urchin-like Fe2O3@CuSiO3 catalyst prepared by the method according to any one of claims 1-7, characterized in that, The Fe2O3@CuSiO3 is used in the electrochemical reduction reaction of CO2 to produce C product.

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