In-situ electrochemical reconstruction Bi0-Bi2O2CO3 nanosheet catalyst as well as preparation and application thereof
By in situ electrochemical reconstruction of Bi0-Bi2O2CO3 nanosheet catalysts, the problems of insufficient selectivity and stability of bismuth-based catalysts in the electrocatalytic reduction of carbon dioxide to formic acid were solved, and efficient and stable CO2 reduction to formic acid was achieved.
Patent Information
- Application Number
- CN202510755781.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-07
- Publication Date
- 2025-09-26
AI Technical Summary
Existing bismuth-based catalysts have problems with selectivity and stability in the electrocatalytic reduction of carbon dioxide to formic acid, and there is a lack of commercial catalysts that simultaneously meet the requirements of high activity, selectivity and stability.
In situ electrochemical reconstruction of Bi0-Bi2O2CO3 nanosheet catalyst was adopted. By growing Bi2O2CO3 nanosheets on carbon support, a new reaction interface was constructed, and the catalyst was prepared by combining solvothermal reaction with in situ electrochemical reconstruction method.
The selectivity and stability of bismuth-based catalysts in electrocatalytic CO2 reduction to formic acid are improved, and the catalysts have high electrocatalytic efficiency, making them suitable for high-selectivity and high-stability electrocatalytic CO2 reduction to formic acid.
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Figure CN120700518A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of bismuth-based nanomaterial synthesis and electrochemical energy conversion, and in particular to a method for in-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst and its preparation and application. Background Art
[0002] Converting carbon dioxide (CO2) into high-value-added chemicals is a sustainable technological solution to alleviate global environmental challenges and resource shortages. The electrocatalytic carbon dioxide reduction reaction (CO2RR) utilizes renewable electricity to convert CO2 into liquid fuels and chemicals. Formic acid is a common raw material in the pharmaceutical and chemical industries and a potential hydrogen storage material in the CO2RR product or energy carrier for direct formic acid fuel cells. The electrochemical reduction of CO2 to formate requires only two electrons, making the process simple and energy-efficient.
[0003] Transition metal-based electrocatalysts (such as Sn, In, Pd, etc.) can selectively convert CO2 into formic acid, but they have problems such as high cost, strong toxicity and poor stability. In contrast, bismuth-based catalysts have low toxicity and low cost, and have significant advantages in the electrocatalytic CO2RR to formic acid. However, the selectivity of bismuth-based catalysts for formic acid and formates in the electrocatalytic carbon dioxide reduction process needs to be improved, and the poor stability of bismuth-based catalysts also limits their large-scale application. Although the advantages and disadvantages of bismuth-based catalysts have received much attention, there is still a lack of commercial bismuth-based catalysts that meet the requirements of high activity, selectivity and stability, and further development and research are still needed.
[0004] In summary, the development of a new bismuth-based catalyst and preparation method to construct a new reaction interface to improve the selectivity and reaction efficiency of CO2RR to produce formic acid is of great significance for promoting the controllable preparation of related materials. Summary of the Invention
[0005] The present invention aims to provide an in-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst and its preparation and application, the present invention in situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst improves the selectivity of bismuth-based catalysts in the electrocatalytic reduction of CO2 to formic acid / formate, has high electrocatalytic efficiency and stability, and can be used for highly selective and stable electrocatalytic reduction of CO2 to produce formic acid.
[0006] The first aspect of the present invention provides an in situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst, comprising a carbon support and Bi2O2CO3 electrochemically grown in situ on the surface of the carbon support 0-Bi2O2CO3 nanosheets, wherein the crystal planes of the nanosheets include Bi2O2CO3 (020) crystal planes and Bi 0 (012) crystal plane.
[0007] Optionally, the carbon carrier includes carbon paper and carbon cloth. In fact, when carbon paper is selected as the carbon carrier, the surface flatness of the carbon paper is high, which is conducive to Bi 0 -Bi2O2CO3 nanosheets are evenly loaded, with good electrical conductivity and mechanical support; when carbon cloth is used as the carbon carrier, local aggregation is prone to occur. 0 -Bi2O2CO3 nanosheets are unevenly distributed, but the carbon cloth is highly flexible, can be bent and cut, and is more corrosion-resistant in acidic / alkaline media.
[0008] Specifically, the reconstruction Bi 0 -Bi2O2CO3 nanosheets include Bi 0 Nanoparticles and Bi2O2CO3 carrier, wherein Bi 0 The nanoparticles are loaded on Bi2O2CO3 support.
[0009] The second aspect of the present invention provides an in situ electrochemical reconstruction of Bi 0 -The preparation method of Bi2O2CO3 nanosheet catalyst comprises the following steps:
[0010] Step 1: Preparation of Bi 0 -Bi2O2CO3 precursor: Dissolve Bi(NO3)3·5H2O in N,N-dimethylacetamide, transfer to a hydrothermal reactor for hydrothermal reaction, wash and dry after the reaction, and collect Bi 0 -Bi2O2CO3 precursor;
[0011] Step 2: Prepare Bi 0 -Bi2O2CO3 catalyst ink: Bi 0 -Bi2O2CO3 precursor was ultrasonically dispersed in a mixed solution of ultrapure water, ethanol and Nafion solution to prepare Bi 0 -Bi2O2CO3 catalyst ink;
[0012] Step 3: In-situ electrochemical reconstruction: Bi 0 -Bi2O2CO3 catalyst ink was drop-coated on carbon paper, dried, and placed in a CO2-saturated KHCO3 solution. A potential was applied for electrolysis to obtain in-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst.
[0013] Optionally, the mass concentration of Bi(NO₃)₃·5H₂O dissolved in N,N-dimethylacetamide in step 1 is 0.015-0.021 g / mL. In fact, N,N-dimethylacetamide (DMF) not only effectively dissolves Bi(NO₃)₃·5H₂O as a solvent, ensuring a stable solvothermal reaction, but also has a reducing effect, further promoting the reaction.
[0014] Optionally, the hydrothermal reaction in step 1 is carried out at a temperature of 120° C.-180° C. for 12-36 hours; the washing and drying comprises washing with ethanol three times, and then vacuum drying at 60° C. overnight.
[0015] Optionally, the Bi in step 2 0 -The mass concentration of Bi2O2CO3 precursor dispersed in the mixed solution is 4-6 mg / mL.
[0016] Optionally, in step 2, the volume ratio of ultrapure water, ethanol and Nafion solution in the mixed solution is 300:(670-710):5; the concentration of the Nafion solution is 5%; and the ultrasonic dispersion lasts for 45-65 minutes.
[0017] Optionally, the ink droplets in step 3 are applied at a density of 0.5-1.2 mg / cm 2 The loading amount is drop-coated on carbon paper; the molar concentration of the KHCO3 solution is 0.5 M; the applied potential is -0.5 V to -1.5 V vs. RHE; and the electrolysis lasts for 45-65 min.
[0018] The third aspect of the present invention provides an in-situ electrochemically reconstructed Bi prepared by any of the above items or any of the methods. 0 -Application of Bi2O2CO3 nanosheet catalyst in electrocatalytic reduction of CO2 to formic acid. 0 -Bi2O2CO3 nanosheet catalyst can highly selectively electrocatalyze the reduction of CO2 to formic acid, with high electrocatalytic efficiency and stability.
[0019] Beneficial effects of the present invention:
[0020] (1) The present invention provides a new bismuth-based catalyst: in situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst, comprising a carbon support and Bi2O2CO3 electrochemically grown in situ on the surface of the carbon support 0 -Bi2O2CO3 nanosheets. 0 -Bi2O2CO3 nanosheets include Bi2O2CO3(020) and Bi 0(012) crystal plane, constructing a new reaction interface. The bismuth-based nanosheet catalyst not only has high stability but also has high selectivity in the electrocatalytic reduction of CO2 to formic acid / formate.
[0021] (2) In-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst preparation method, using low-cost and less toxic Bi(NO3)3·5H2O as raw material, based on carbon paper support, a simple one-step solvent thermal reaction combined with in situ electrochemical reconstruction to prepare the above-mentioned Bi 0 -Bi2O2CO3 nanosheet catalyst. This preparation method not only has the potential for large-scale production, but is also expected to provide an effective strategy for the preparation of other materials. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 The Bi prepared in step 1 of Example 1 of the present invention is 0 -XRD pattern of Bi2O2CO3 precursor;
[0023] Figure 2 The in-situ electrochemically reconstructed Bi prepared in step 3 of Example 1 of the present invention 0 -XRD pattern of Bi2O2CO3 nanosheet catalyst;
[0024] Figure 3 This is a Faraday efficiency diagram for the electrocatalytic reduction of CO2 to formic acid in Example 2 of the present invention;
[0025] Figure 4 This is a diagram showing the catalyst stability of the electrocatalytic reduction of CO2 to formic acid in Example 3 of the present invention;
[0026] Figure 5 Bi prepared in step 1 of Example 1 of the present invention 0 -SEM image of Bi2O2CO3 precursor;
[0027] Figure 6 The in-situ electrically reconstructed Bi prepared in step 3 of Example 1 of the present invention is 0 -Scanning electron microscope image of Bi2O2CO3 nanosheet catalyst. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs.
[0029] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.
[0030] Example 1
[0031] This embodiment provides an in-situ electrochemical reconstruction of Bi 0 -The preparation method of Bi2O2CO3 nanosheet catalyst comprises the following steps:
[0032] Step 1: Preparation of Bi 0 -Bi2O2CO3 precursor: First, 0.3g Bi(NO3)3·5H2O was dissolved in 17mL N,N-dimethylacetamide (DMF), and the mixed solution was transferred to a 50mL polytetrafluoroethylene-lined autoclave and reacted at 150℃ for 24h; after the reaction, the product was collected, washed with ethanol and dried in vacuum at 60℃ overnight to obtain Bi 0 -Bi2O2CO3 precursor, its XRD pattern is as follows Figure 1 As shown;
[0033] Step 2: Prepare Bi 0 -Bi2O2CO3 catalyst ink: 5mg Bi 0 -Bi2O2CO3 precursor was ultrasonically dispersed in a mixed solution of 300 μL ultrapure water, 690 μL ethanol and 10 μL 5% Nafion solution, and ultrasonication was continued for 1 h to prepare Bi 0 -Bi2O2CO3 catalyst ink;
[0034] Step 3: In-situ electrochemical reconstruction: Bi prepared in step 2 0 -Bi2O2CO3 catalyst ink 1mg / cm 2 The loaded amount was drop-coated on carbon paper, dried, and placed in a CO2-saturated 0.5M KHCO3 solution. Electrolysis was performed at a potential of -1.0V vs. RHE for 1 h to obtain in situ electrochemically reconstructed Bi 0 -Bi2O2CO3 nanosheet catalyst, its XRD pattern is as follows Figure 2As shown, 27° and 46.9° in the spectrum represent Bi 0 (012) crystal plane and Bi2O2CO3(020) crystal plane.
[0035] Example 2
[0036] This example is a method for the in-situ electrochemical reconstruction of Bi prepared in Example 1. 0 -Bi2O2CO3 nanosheet catalyst was tested for activity, including the in-situ electroreconstruction of Bi prepared in Example 1. 0 -Bi2O2CO3 nanosheet catalyst was measured in an H-type electrolyzer, and the catalytic activity curve of electrocatalytic reduction of CO2 in 0.5M KHCO3 solution was plotted. The specific implementation was as follows:
[0037] (1) Using an electrochemical workstation to test with a three-electrode system, the Bi 0 -Bi2O2CO3 nanosheet catalyst was used as the working electrode, and its area immersed in 0.5M KHCO3 solution was 1cm 2 , platinum sheet was used as counter electrode and Ag / AgCl as reference electrode;
[0038] (2) The chronoamperometry method was used, with the initial potential set at -0.6 V and the end potential set at -1.3 V. The test was conducted every 0.1 V for 30 min, and the gas products were detected by online gas chromatography. H2 and CO2 were analyzed using a thermal conductivity detector (TCD) on a Haysep Q column, while hydrocarbon products were detected using a flame ionization detector (FID) on an alumina column. Liquid products were analyzed using 1H nuclear magnetic resonance spectroscopy. The calculated Faradaic efficiency of formic acid is shown in the following figure. Figure 3 As shown;
[0039] Among them, the calculation formula of the gas product Faraday efficiency is: x0 is the gas product concentration (mol / mol) determined by gas chromatography, n is the number of moles of gas, N A is Avogadro's constant, Z is the number of electrons required to generate 1 mol H2, The recorded current (i0) and the sample loop purge injection time (t) are used to calculate the Faradaic efficiency of the liquid product; the liquid product Faradaic efficiency calculation formula is: N HCOOH =C HCOOH ×n×N A ×Ze, C HCOOH represents the concentration of formate in the solution (calculated according to the calibration curve), V represents the volume of the electrolyte in the cathode chamber, and Q0 represents the amount of transferred charge.
[0040] Example 3
[0041] This example is a method for the in-situ electrochemical reconstruction of Bi prepared in Example 1. 0 -Bi2O2CO3 nanosheet catalyst was tested for stability, including the in-situ electroreconstruction of Bi prepared in Example 1. 0 -Bi2O2CO3 nanosheet catalyst was tested in an H-type electrolyzer, and the stability curve of electrocatalytic reduction of CO2 in 0.5M KHCO3 solution was plotted. The specific implementation was as follows:
[0042] (1) Using an electrochemical workstation to test with a three-electrode system, the Bi 0 -Bi2O2CO3 nanosheet catalyst was used as the working electrode, and its area immersed in 0.5M KHCO3 solution was 1cm 2 , platinum sheet was used as counter electrode and Ag / AgCl as reference electrode;
[0043] (2) The material was tested using a constant potential test method, with the potential set at -0.9 V, and the working curve was recorded. Figure 4 During the stability test, gas products were detected by gas chromatography;
[0044] according to Figure 4 As shown, the above-mentioned in-situ electrical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst has excellent stability in electrocatalytic reduction of CO2 to formic acid.
[0045] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.
Claims
1. An in-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst, characterized in that The invention comprises a carbon support and a Bi2O3 layer electrochemically grown in situ on the surface of the carbon support. 0 -Bi2O2CO3 nanosheets, wherein the crystal planes of the nanosheets include Bi2O2CO3 (020) crystal planes and Bi 0 (012) crystal plane.
2. Bi according to claim 1 0 -Bi2O2CO3 nanosheet catalyst, characterized in that The carbon support includes carbon paper and carbon cloth.
3. Bi according to claim 1 0 -Bi2O2CO3 nanosheet catalyst, characterized in that The nanosheets include Bi 0 Nanoparticles and Bi2O2CO3 carrier, wherein Bi 0 The nanoparticles are loaded on Bi2O2CO3 support.
4. A Bi according to any one of claims 1 to 3 0 -A method for preparing a Bi2O2CO3 nanosheet catalyst, characterized in that: The following steps are involved: Step 1: Preparation of Bi 0 -Bi2O2CO3 precursor: Dissolve Bi(NO3)3·5H2O in N,N-dimethylacetamide, transfer to a hydrothermal reactor for hydrothermal reaction, wash and dry after the reaction, and collect Bi 0 -Bi2O2CO3 precursor; Step 2: Prepare Bi 0 -Bi2O2CO3 catalyst ink: Bi 0 -Bi2O2CO3 precursor was ultrasonically dispersed in a mixed solution of ultrapure water, ethanol and Nafion solution to prepare Bi 0 -Bi2O2CO3 catalyst ink; Step 3: In-situ electrochemical reconstruction: Bi 0 -Bi2O2CO3 catalyst ink was drop-coated on carbon paper, dried, and placed in a CO2-saturated KHCO3 solution. A potential was applied for electrolysis to obtain in-situ electrochemical reconstruction of Bi 0 -Bi2O2CO3 nanosheet catalyst.
5. The preparation method according to claim 3, characterized in that The mass concentration of Bi(NO3)3·5H2O dissolved in N,N-dimethylacetamide in step 1 is 0.015-0.021 g / mL.
6. The preparation method according to claim 3, characterized in that The hydrothermal reaction in step 1 is carried out at a temperature of 120° C.-180° C. for 12-36 hours; the washing and drying comprises washing with ethanol three times, and then vacuum drying at 60° C. overnight.
7. The preparation method according to claim 3, characterized in that Bi in step 2 0 -The mass concentration of Bi2O2CO3 precursor dispersed in the mixed solution is 4-6 mg / mL.
8. The preparation method according to claim 3, characterized in that The volume ratio of ultrapure water, ethanol and Nafion solution in the mixed solution in step 2 is 300:(670-710):5; the concentration of the Nafion solution is 5%; and the ultrasonic dispersion lasts for 45-65 minutes.
9. The preparation method according to claim 3, characterized in that The ink droplets in step 3 are applied at 0.5-1.2 mg / cm 2 The loading amount is drop-coated on carbon paper; the molar concentration of the KHCO3 solution is 0.5 M; the applied potential is -0.5 V to -1.5 V vs. RHE; and the electrolysis lasts for 45-65 min.
10. A Bi according to any one of claims 1 to 2 0 -Bi2O2CO3 nanosheet catalyst or Bi prepared by the method according to any one of claims 3 to 8 0 -Application of Bi2O2CO3 nanosheet catalyst in electrocatalytic reduction of CO2 to formic acid.