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CN-121992441-A - Process for the preparation of formic acid

CN121992441ACN 121992441 ACN121992441 ACN 121992441ACN-121992441-A

Abstract

The invention relates to the technical field of electrochemical reduction of carbon dioxide, and particularly discloses a preparation method of formic acid, which comprises the steps of carrying out electrochemical reduction on a material containing carbon dioxide, wherein a cathode electrode used during the electrochemical reduction comprises a titanium-doped bismuth-based material, the titanium-doped bismuth-based material has a nanorod morphology, the titanium-doped bismuth-based material with the nanorod morphology is used as an electrocatalyst, hydrogen evolution reaction in the electrochemical reduction reaction is inhibited, the selectivity of the formic acid is remarkably improved, and the material has long-term stability in an electrolytic cell, and can be used for efficiently reducing the carbon dioxide into pure formic acid in a solid electrolytic cell.

Inventors

  • LI YUHANG
  • LI CHUNZHONG
  • ZHANG LING
  • YANG ZIYAN
  • YANG CHUNQI
  • Sun Ruoyue

Assignees

  • 华东理工大学

Dates

Publication Date
20260508
Application Date
20260209

Claims (10)

  1. 1. The preparation method of the formic acid is characterized by comprising the step of carrying out electrochemical reduction on a material containing carbon dioxide, wherein a cathode electrode used in the electrochemical reduction comprises a titanium-doped bismuth-based material, and the titanium-doped bismuth-based material has a nanorod morphology.
  2. 2. The method of claim 1, wherein the titanium doped bismuth-based material comprises bismuth titanate.
  3. 3. The method according to claim 1 or 2, wherein the preparation method of the titanium doped bismuth based material comprises: s1, mixing a bismuth source, a titanium source and an inorganic alkali solution to obtain a suspension; s2, carrying out a hydrothermal reaction on the suspension to obtain a hydrothermal reaction product; and S3, calcining the product of the hydrothermal reaction.
  4. 4. A process according to claim 3, wherein the molar ratio of bismuth source to titanium source is (0.5-2): 1, preferably (0.8-1.5): 1; and/or the temperature of the hydrothermal reaction is 160-200 ℃; And/or the hydrothermal reaction time is 18-24 hours; and/or the calcination temperature is 400-800 ℃; and/or the calcination time is 1-4h.
  5. 5. The method of any of claims 1-4, wherein the titanium doped bismuth based material has a nanorod morphology with an aspect ratio of ≡2.
  6. 6. The method of any one of claims 1-5, wherein the cathode electrode comprises 0.8-1.5mg cm -2 of the titanium-doped bismuth-based material.
  7. 7. The method of claim 6, wherein the cathode electrode is a carbon sheet electrode loaded with the titanium doped bismuth based material.
  8. 8. The method of any of claims 1-7, wherein the electrochemical reduction comprises performing electrochemical reduction in a flowing cell or a solid electrolyte cell.
  9. 9. The method of any one of claims 1-8, wherein the electrochemical reduction has a current density of 100-300 mA cm -2 .
  10. 10. The method of any one of claims 1-9, wherein the electrolyte used in performing the electrochemical reduction comprises bicarbonate; preferably, the bicarbonate concentration is 0.5-2mol/L.

Description

Process for the preparation of formic acid Technical Field The invention relates to the technical field of electrochemical reduction of carbon dioxide, in particular to a preparation method of formic acid. Background Carbon dioxide conversion technology is of great interest. Among them, the electrocatalytic reduction technology of carbon dioxide is used as a high-efficiency carbon capturing and utilizing means, and has become one of key technologies for coping with climate change and reducing greenhouse gas emission. Formic acid is one of the main products of carbon dioxide reduction, and has important application value in chemical synthesis and energy storage. Formic acid is not only an important raw material in the chemical industry, but also can be used as an effective hydrogen source and energy carrier, and plays a key role in fuel cells and energy storage. Formic acid has a higher energy density and lower environmental load than other carbon dioxide reduction products and is therefore considered to be an ideal target product in carbon dioxide reduction technology. Bismuth-based catalysts have been shown to have catalytic activity for the reduction of CO 2 to formic acid, where bismuth-oxygen bonds (Bi-O) are key active sites of bismuth-based catalysts, however, bismuth-based catalysts have competing hydrogen evolution reactions in electrochemical reduction reactions, severely interfering with formic acid formation, and bismuth-based catalysts cannot react for long periods of time due to poor stability. Disclosure of Invention The invention aims to solve the technical problems that the bismuth-based catalyst has competitive hydrogen evolution reaction in electrochemical reduction reaction and seriously interferes with the generation of formic acid, and the bismuth-based catalyst cannot react for a long time due to poor stability, and provides a preparation method of the formic acid. In order to achieve the aim, the invention provides a preparation method of formic acid, which comprises the steps of carrying out electrochemical reduction on a material containing carbon dioxide, wherein a cathode electrode used in the electrochemical reduction comprises a titanium-doped bismuth-based material, and the titanium-doped bismuth-based material has a nanorod morphology. Through the technical scheme, the invention has at least the following beneficial effects: 1. The invention discovers that the titanium doped bismuth-based material with the shape of the nano rod is used as an electrocatalyst for preparing formic acid by electrochemical reduction of carbon dioxide, the selectivity of the formic acid is higher, and the Faraday efficiency of the formic acid can reach more than 90% in the wide current density range from 100 mA cm -2 to 300 mA cm -2; 2. The invention discovers that the titanium doped bismuth-based material with the shape of the nano rod is taken as an electrocatalyst for preparing formic acid by electrochemical reduction of carbon dioxide, and can generate structural transformation to generate bismuth subcarbonate, and the structural transformation process endows the material with excellent durability and stable catalytic selectivity in the reaction process, so that the overall electrocatalysis performance is remarkably improved; 3. the preparation method of the formic acid can be used in a flowing electrolytic cell, and the titanium doped bismuth-based material can realize the Faraday efficiency of the formic acid of more than 90 percent in the flowing electrolytic cell within the current density range of 100 to 300 mA cm -2. At a current density of 200 mA cm -2, the Faraday efficiency of formic acid can be maintained to be higher than 90% for more than 24 hours, and excellent selectivity and stability are shown; 4. The preparation method of formic acid can be used in a solid electrolytic cell, and can stabilize the Faraday efficiency of formic acid to be higher than 70% for more than 48 hours when the current density is 100 mA cm -2, and can efficiently prepare pure formic acid. Drawings FIG. 1 is a TEM image of Bi 4Ti3O12 obtained in preparation example 1 and a SEM image of Bi 2O3 obtained in comparative preparation example 1, wherein FIG. 1a is a TEM image of Bi 4Ti3O12 obtained in preparation example 1 and FIG. 1b is a SEM image of Bi 2O3 obtained in comparative preparation example 1; FIG. 2 is an XRD spectrum of the material obtained in preparation examples 1-3 and comparative preparation example 1, wherein FIG. 2a is an XRD spectrum of Bi 4Ti3O12 obtained in preparation example 1, FIG. 2b is an XRD spectrum of-1 obtained in preparation example 2, FIG. 2c is an XRD spectrum of-2 obtained in preparation example 3, and FIG. 2d is an XRD spectrum of Bi 2O3 obtained in comparative preparation example 1; FIG. 3 is a graph showing the results of the Faraday efficiency test of hydrogen and formic acid for electrochemical reduction of carbon dioxide in a flow cell for Bi 4Ti3O12 obtained in preparatio