Preparation Of Bi₂O₃ And In Nano Electrode Materials And Electrocatalytic Reduction Of CO₂

Electrochemical catalytic reduction of carbon dioxide can be transformed into high value-added chemical products,such as HCOOH,C₂H₅OH,CO,CH₄,C₂H₄,etc.Electrochemical methods have been attracted more attention due to their green,efficient and easy to be applied in industry.So far,a variety of electrocatalysts?electrode materials?have been developed for the exploration of electrocatalytic CO₂ reduction.However,there are still some shortcomings,such as low catalytic activity and poor stability of electrode materials.Therefore,it is necessary to develop efficient and stable electrode catalytic materials.In this paper,bismuth-based and indium-based nano materials are taken as the research objects,and the activity and stability of electrode catalysts are improved through the composition of electrode materials,the regulation of micro-morphology and structure of electrode surface,and the optimization of electrolysis conditions.Bi₂O₃ nanoparticles and spherical nano In electrode catalysts with high selectivity,electrochemical activity and stability were designed and prepared respectively.SEM,XRD,XPS and other analytical methods were used to analyze and characterize the prepared nano electrode catalysts in terms of its microscopic morphology,crystal structures,element compositions,etc.Meanwhile,electrochemical properties such as LSV,CV and i-t were tested by potentiostatic electrolysis.The main research contents and conclusions of this paper are as follows.?1?Hydrothermal and chemical precipitation methods were used to prepare Bi₂O₃-A nanoparticles and Bi₂O₃-B thin nanorod electrodes with different morphologies.It was found that Bi₂O₃-A nanoparticles had better electrocatalytic activity for electrochemical reduction of CO₂ into formate by electrolysis at constant potential-1.2 V,and their current density was up to 22 mA cm^-2,and Faraday efficiency was 91%,compared with Bi₂O₃-B thin nanorod electrode catalyst.The main reason for this phenomenon is that under the same conditions,the unique crystal structure of Bi₂O₃-A nanoparticles leads to the larger specific surface area,which can provide a large number of catalytic active sites.And it is beneficial to the formation of intermediate CO₂^?-.More importantly,its electrochemical activity showed no significant attenuation?>90%?within electrolysis for 22 h,indicating good electrocatalytic stability.?2?Controling the polishing time of copper foil prepared substrate materials with different roughness.Under the same conditions,In nanoparticles were prepared by electrodeposition.The results showed that there were significant differences in the microstructure of the coating metals formed by electrodeposition on the substrate with different degrees of polishing.The nano spherical particle In could be formed on the Cu foil substrate obtained with polishing 8min by the electrodeposition,which showed excellent electrochemical catalytic properties.At the same time,by comparison with the single metal In foil,it was found that the Faraday efficiency of formate produced by the nano spherical In electrode at-1.2 V was significantly higher than that of In foil electrode under the same condition.More interestingly,nano spherical In electrode catalyst had a larger active surface area and improved electrical conductivity,leading to an effective improvement in its catalytic activity.The results showed that Faraday efficiency of formate was not significantly changed within the electrolysis for 18 h(>=87.5%,16 mA cm^-2),indicating that nano spherical In electrode catalyst had a good electrocatalytic stability.