In-situ Reconstruction Of Bimetallic Catalysts And Electrochemical Catalytic Reduction Of Carbon Dioxide

With the proposal of the national major strategic decision of "dual carbon",the climate problem caused by excessive carbon dioxide emissions has once again been pushed to the forefront.The electrocatalytic reduction of carbon dioxide reaction system can utilize renewable energy to provide electricity and reduce carbon dioxide into high value-added chemicals.This is of great significance for obtaining the carbon cycle,and has become the current research hotspot.Carbon dioxide can be converted into different products through electron acquisition,protonation,carbon carbon coupling and other processes,and its reaction path is complex.There is often a problem of poor selectivity when electro reducing carbon dioxide into multi carbon products.However,the reaction of reducing carbon dioxide to formic acid and carbon monoxide through a two electron transfer process is relatively easy to regulate in selectivity and is the most economically feasible.Therefore,precise regulation of the synthesis of catalysts with high catalytic activity and selectivity is a key issue in obtaining target products and expanding production scale.Research has shown that metal based catalysts exhibit excellent catalytic activity for electrocatalytic reduction of carbon dioxide.Among them,bimetallic catalysts are a class of important inorganic materials with broad application value for electrocatalytic reduction of carbon dioxide because of their rich composition,unique electronic structure and metal metal synergy.In addition,with the development of in-situ characterization technology,people gradually have a deeper understanding of the evolution process of the in-situ structure of the catalyst,which can not be ignored to explore the real active site of the catalyst and the reaction mechanism.Therefore,in this article,we synthesized various bimetallic catalysts through morphology controlled synthesis,doping techniques,and heterostructure construction,which were applied in the electrocatalytic reduction of carbon dioxide reaction.Among them,h-Cu Bi2O4 spinel material and Cu/Bi2S3-2.67% catalyst show better selectivity for formic acid.The Faraday efficiency FEHCOOH is up to 95%,and the current density measured in the flow electrolytic cell is greater than 200 m A cm-2.The Sn-Cu O-2.32%,Cu In5% and Cu Sn3%materials have the best catalytic effect on carbon monoxide generation.With the introduction of tin and indium atoms,the catalytic activity and selectivity of CO can be effectively regulated,and FECO can reach 98% at low overpotential.The experimental results and theoretical calculations show that the high performance of the catalyst is inseparable from the structural stability,electronic structure regulation and interface effect.Combining in situ technique to explore the process of structural change of catalysts,understand the reaction mechanism and the relationship between structure and performance,which has important implications for the design and synthesis of catalysts with high catalytic activity and selectivity.In this paper,the reconstruction process of catalyst was revealed by in situ Raman,in situ detection attenuated total reflection infrared spectroscopy,in situ electron microscopy and quasi situ X-ray diffraction techniques.The results show that the reduction phase transition to zero or low price is common,and the morphology and surface electronic structure of catalysts are affected by the reduction potential and microscopic environment.In addition,the reaction intermediates were successfully detected,indicating the formation paths of formic acid and carbon monoxide.It is through the coupling of an electron and a proton obtained by CO2 that *OCHO and *COOH reaction intermediates are formed on the catalyst surface respectively,which provides evidence for clarifying the catalytic reaction path.