Preparation method of CH3COO (BiO) and application of CH3COO (BiO) in production of formic acid by reducing CO2 through electro-catalysis
By preparing and applying CH3COO (BiO) catalyst, the problems of low current density and narrow potential window in electrocatalytic CO2 reduction of Bi-based catalysts are solved, and higher formic acid production selectivity and current density are achieved, and higher Stability and environmental friendliness.
Patent Information
- Application Number
- CN202411346117.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-26
- Publication Date
- 2024-12-31
AI Technical Summary
In the field of electrocatalytic reduction of carbon dioxide to formate, existing Bi-based catalysts have problems such as low current density, narrow potential window, and the selectivity of formic acid needs to be improved.
CH3COO (BiO) is used as a catalyst, and mixed grinding of Bi(NO3)3·5H2O and CH3COONa is mixed with a molar ratio of 1:1 to 5. It is used as a catalyst for electrocatalyzing CO2 reduction formic acid production, and is uniform in the electrolyte. In the form of a mass ink, the electrocatalytic reaction conditions are -0.7 to -1.5V vs RHE, CO2 saturated aqueous phase electrolysis, CH3COO (BiO) is dispersed in a mixed solution of ethanol, water and Nafion, and the electrolyte is 0.3 to 0.8M KHCO3 The CO2 flow rate for solution is 15-25 mL/min.
The selectivity and current density of formic acid are improved within the wide potential window of 700mV. Bi3+ activates CO2 and Bi0 promotes HCO3-adsorption and proton-coupled electron transfer reactions. The CH3COO (BiO) in the layered structure avoids the agglomeration of metal Bi, and improves the agglomeration of metal Bi, which increases the The stability and catalytic activity of the catalyst are achieved.
Smart Images
Figure CN119219486A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of electrochemical reduction of CO2 catalysis, and specifically relates to a preparation method of CH3COO(BiO) and application of the same in electrocatalytic reduction of CO2 to produce formic acid. Background Art
[0003] In recent years, the electrochemical catalytic CO2 reduction reaction (ECO2RR) powered by renewable energy has become the forefront of the current CO2 conversion field due to its environmental friendliness, operation at room temperature and pressure, and mild reaction. There are many products obtained by the electrocatalytic reduction of carbon dioxide. Among them, formic acid, as a safe and convenient liquid fuel, has the advantages of high volumetric energy density and easy transportation and storage. It is one of the basic organic chemical raw materials and is widely used in industrial fields such as pesticides, leather, dyes, and medicine. Compared with methanol, CO and other long-chain hydrocarbon compounds, formic acid has higher commercial value and is a more ideal CO2 reduction product. In the field of electrocatalytic reduction of carbon dioxide to formate, Bi-based catalysts show excellent formic acid production performance, but there are still problems such as low current density, narrow potential window, and the selectivity for formic acid needs to be improved. Summary of the invention
[0004] The object of the present invention is to provide a method for preparing CH3COO(BiO) and its application in electrocatalytic CO2 reduction to produce formic acid, which has higher formic acid selectivity and formic acid production current density within a wide potential window of 700mV compared with metal Bi catalysts.
[0005] The technical solution of the present invention is as follows:
[0006] A preparation method of CH3COO(BiO) comprises mixing and grinding Bi(NO3)3·5H2O and CH3COONa in a molar ratio of 1:1-5 to obtain CH3COO(BiO), wherein the mixing and grinding time is 0.5-4h.
[0007] Application of CH3COO(BiO) as catalyst in electrocatalytic CO2 reduction to formic acid.
[0008] In some possible implementations, the potential of the electrocatalytic reaction is -0.7 to -1.5 V vs RHE, the time of the electrocatalytic reaction is 0.5 to 1.5 h, and the electrocatalytic reaction is carried out in a CO2-saturated aqueous electrolyte.
[0009] In some possible implementations, CH3COO(BiO) is dispersed in a mixed solution of ethanol, water, and Nafion to form a homogeneous ink;
[0010] The concentration of CH3COO(BiO) in the homogeneous ink is 10 mg / L.
[0011] In some possible implementations, the volume ratio of ethanol, water and Nafion is 1:10-15:10-15.
[0012] In some possible implementations, CH3COO(BiO) is prepared by the preparation method of claim 1.
[0013] In some possible implementations, the electrolyte is a 0.3-0.8 M KHCO3 solution.
[0014] In some possible implementations, CO2 is continuously introduced at a flow rate of 15 to 25 mL / min during the electrocatalytic reaction.
[0015] The present invention has at least the following beneficial effects:
[0016] (1) The present invention applies CH3COO(BiO) to the electrocatalytic CO2 reduction reaction to produce formic acid. 3+ It is beneficial to the activation of CO2, and Bi 0 Promotes HCO3 - The adsorption and proton-coupled electron transfer reaction together improve the catalytic activity of the catalyst ECO2RR. In addition, CH3COO(BiO) has a layered structure, which can prevent the agglomeration of metal Bi during the electrolysis process, making it more stable and able to continue catalysis. Compared with metal Bi catalysts, CH3COO(BiO) has higher formic acid selectivity and formic acid production current density in a wide potential window of 700mV (-0.8~1.4V vs RHE).
[0017] (2) CH3COO(BiO) as a Bi-based catalyst is environmentally friendly, and the preparation method provided by the present invention also has the advantages of simple process, easy operation and industrial scale-up. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 1 is the XRD spectrum of CH3COO(BiO) (a) prepared in Example 1 and the metal Bi powder (b) used in Comparative Example 1;
[0019] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum of the liquid product obtained by in-situ reduction of the working electrode (a) prepared in Example 1 and the comparative working electrode (b) prepared in Comparative Example 1 at a potential of -0.9 V vsRHE for 1 h;
[0020] Figure 3is the Faradaic efficiency of the working electrode (BiOAc) prepared in Example 1 and the comparative working electrode (Bi) prepared in Comparative Example 1 in an H-type electrolytic cell;
[0021] Figure 4 1 is the partial current density of formic acid of the working electrode (BiOAc) prepared in Example 1 and the comparative working electrode (Bi) prepared in Comparative Example 1 in an H-type electrolytic cell. DETAILED DESCRIPTION
[0022] The technical solution of the present invention is further illustrated and described below through specific implementation methods.
[0023] In the following examples and comparative examples, the water used can be one or more of distilled water, purified water, and drinking water; unless otherwise specified, the detection methods in the following examples are conventional detection methods; unless otherwise specified, the reagents in the following examples are purchased from commercial channels. The metal Bi powder used in Comparative Example 1 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a product number of B163040 and a purity of ≥99.9%.
[0024] In the following examples and comparative examples, the electrocatalytic CO2 reduction reaction to produce formic acid (hereinafter referred to as electrocatalytic reaction) is carried out in an H-type electrolytic cell, and the anode and cathode are separated by a Nafion117 diaphragm. The reaction is carried out through a three-electrode system, wherein the working electrode is a carbon paper coated with a homogeneous ink obtained by mixing CH3COO (BiO) or Bi powder, ethanol, water and Nafion, the auxiliary electrode is a platinum electrode, and the reference electrode is a silver / silver chloride electrode, and the reaction is carried out under a continuous CO2 atmosphere.
[0025] Example 1
[0026] CH3COO(BiO)(BiOAc) is used as a catalyst for electrocatalytic production of formic acid from carbon dioxide. The specific implementation steps are as follows:
[0027] (1) 1 mmol Bi(NO3)3·5H2O and 5 mmol CH3COONa were mixed and ground in an agate mortar for about 30 min, then washed three times with ethanol and deionized water alternately, and then placed in a forced air drying oven at 60°C overnight to obtain CH3COO(BiO);
[0028] (2) 10 mg of CH3COO(BiO) was placed in 480 μl of ethanol, 480 μl of deionized water and 40 μl of Nafion and ultrasonicated for 30 min to obtain a homogeneous ink. Then 1 mg of the homogeneous ink was drop-coated on carbon paper. After the homogeneous ink was dried, a working electrode was obtained.
[0029] Comparative Example 1
[0030] Bi powder is used as a catalyst and used to electrocatalyze carbon dioxide to produce formic acid. The specific implementation steps are as follows:
[0031] 10 mg of Bi powder was placed in 480 μl of ethanol, 480 μl of deionized water and 40 μl of Nafion and ultrasonicated for 30 min to obtain a homogeneous ink. Then 1 mg of the homogeneous ink was drop-coated on carbon paper. After the homogeneous ink was dried, a comparative working electrode was obtained.
[0032] Performance Testing
[0033] 1. The XRD patterns of CH3COO(BiO) prepared in Example 1 and the Bi powder used in Comparative Example 1 were measured respectively. The results are as follows: Figure 1 As shown, it can be seen that the peak of CH3COO(BiO) corresponds to the standard card PDF#41-0800, and the peak of metal Bi powder corresponds to the standard card PDF#85-1329, indicating that CH3COO(BiO) and metal Bi powder are both pure phase substances.
[0034] 2. The working electrode prepared in Example 1 and the comparative working electrode prepared in Comparative Example 1 were placed in a 0.5M KHCO3 solution saturated with carbon dioxide, and in situ reduced for 1 h at a potential of -0.9 V vs RHE. During the whole process, carbon dioxide was continuously introduced at a flow rate of 20 mL / min. After the reaction, the liquid product was tested by nuclear magnetic resonance hydrogen spectrum. The results are as follows: Figure 2 As shown, it can be seen that the liquid products of both are formic acid.
[0035] 3. The working electrode prepared in Example 1 and the comparative working electrode prepared in Comparative Example 1 were placed in an H-type electrolytic cell to test the performance of carbon dioxide to formic acid. Different electrode potentials (at -0.7 to -1.5 V vs RHE, a value was taken every -0.1 V vs RHE), and high-purity carbon dioxide gas was continuously bubbled into a 0.5 M KHCO3 solution at a flow rate of 20 mL / min. The test was conducted for 1 hour at each electrode potential, and the Faradaic efficiency (FE) of formic acid was measured. HCOOH ) and formic acid current density, the results are as follows Figure 3 and Figure 4 shown.
[0036] Among them, from Figure 3It can be seen that the working electrode prepared in Example 1 shows a formic acid Faradaic efficiency much higher than that of the comparative working electrode prepared in Comparative Example 1 in all tested potential ranges, reaching a peak value of 95.7% at -1.0V vs RHE, which is higher than 93.4% of metal Bi, and at -0.7V vs RHE, the formic acid Faradaic efficiency of metal Bi is only 30% while that of BiOAc is still 70%, indicating that BiOAc has a higher selectivity for producing formic acid. In addition, BiOAc The Faraday efficiency of formic acid is greater than 90% in the voltage range of -0.8 to 1.4 V vs RHE, while the Faraday efficiency of metal Bi is greater than 90% only in the voltage range of 0.9 to 1.2 V vs RHE, indicating that BiOAc Has a larger potential window.
[0037] from Figure 4 It can be seen that the working electrode prepared in Example 1 shows a much higher partial current density of formic acid than the comparative working electrode prepared in Comparative Example 1 in all tested potential ranges, indicating that CH3COO(BiO) has better catalytic activity for ECO2RR.
[0038] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.
Claims
1. A method for preparing CH3COO(BiO), characterized in that: Bi(NO3)3·5H2O and CH3COONa are mixed and ground in a molar ratio of 1:1 to 5 to obtain CH3COO(BiO), wherein the mixing and grinding time is 0.5 to 4 hours.
2. Application of CH3COO(BiO) as catalyst in electrocatalytic CO2 reduction to produce formic acid.
3. The use according to claim 2, characterized in that The potential of the electrocatalytic reaction is -0.7 to -1.5 V vs RHE, the time of the electrocatalytic reaction is 0.5 to 1.5 h, and the electrocatalytic reaction is carried out in a CO2-saturated aqueous electrolyte.
4. The use according to claim 3, characterized in that The CH3COO(BiO) is dispersed in a mixed solution of ethanol, water and Nafion to form a homogeneous ink; Wherein, the concentration of CH3COO(BiO) in the homogeneous ink is 10 mg / L.
5. The use according to claim 4, characterized in that The volume ratio of the ethanol, the water and the Nafion is 1:10-15:10-15.
6. The use according to any one of claims 2 to 5, characterized in that: The CH3COO(BiO) is prepared by the preparation method described in claim 1.
7. The use according to claim 3, characterized in that The electrolyte is a 0.3-0.8M KHCO3 solution.
8. The use according to claim 3, characterized in that During the electrocatalytic reaction, CO2 was continuously introduced at a flow rate of 15 to 25 mL / min.