The Promotion Effects Of Catalytic Surface Properties On Carbon Dioxide Electroreduction

The extensive employment of fossil fuels has greatly improved the social productivity of human society.But such development was followed by serious climate and environment problems.In the long run,the development driven by fossil fuels is unstainable.In order to achieve carbon peak and carbon neutralization,it is necessary to explore the utilization of carbon dioxide.With the advantages of high reaction efficiency and controllable conditions,CO2 electrochemical reduction is one of the most promising methods to realize the industrial utilization of carbon dioxide.The key process of carbon dioxide electrochemical reduction is the electron transfer process between catalysts and reactants or intermediates.The surface properties of catalysts determine the adsorption and reaction process of reactants and intermediates.The adsorption of reactants and intermediates could in turn affect the surface structure and properties of catalysts.As such,the surface structure of one catalyst has a great impact on its catalytic performance.Herein,with the regulation of the surface properties,we developed three kinds of highly efficient electrocatalysts towards CO2 electroreduction.Based on experimental and theoretical perspectives,we conducted deep-going researches on the catalytic reaction mechanism.The specific contents are listed as follow:(1)We electrodeposited two kinds of bismuth caystals:nearly octahedral Bi MP and nanoflake-shaped Bi NF.Surface structure characterization revealed that the exposed surfaces of Bi MP were {003} and {101} planes while the exposed surfaces of Bi NF were {104} and {110} planes.The {101} plane of bismuth was used in CO2 electroreduction for the first time.In spite of much lower electrochemical surface area,Bi MP achieved higher FEHCOO-and jHCOO-with respect to Bi NF.According to kinetic analysis and mechanistic study,highly-oriented surface of Bi MP not only facilitated faradaic process and accelerated reaction kinetics via enhancing the CO2 activation,but also restrained competing hydrogen evolution reaction,thus boosting catalytic performance of the electroreduction of CO2 into HCOO-.(2)We employed hydrothermal method to synthesis lysine functionalized SnO2 nanospheres,denoted as SnO2-lys.During CO2 electroreduction,SnO2-lys achieved higher FEHCOO-and jHCOO-with respect to pristine SnO2.Moreover,SnO2-lys maintained a FEHCOO-of 87%with a partial current density of 351.9 mA cm-2.On account of kinetic analysis and mechanistic study,lysine functionalized SnO2 increased the absorptance capacity of CO2·-intermediates and accelerated faradaic process,thus promoting catalytic performance of the electroreduction of CO2 into HCOO-.(3)We synthesized hexagonal perforated Bi2Te3 nanosheets(PBT-NS)for CO2 electroreduction.During CO2 electroreduction,besides the production of HCOO-,Bi2Te3 also accelerated the formation of C2O42-.At-1.1 V vs.RHE,the FEC2O42-reached a peak at 41.4%.In virtue of kinetic analysis,the faradaic processes for the production of HCOO-and C2O42-were accelerated.Diffuse reflectance infrared Fourier transform spectroscopy confirmed the absorptance of*O2CCO2*intermediates.The perforated structure enlarged the specific surface area of PBT-NS.It could also be deduced by the analysis of electronic states of Bi2Te3 that the band inversion enhanced the formation of HCOO-while the topological protected surface states facilitated the formation of C2O42-.Our work is of great significance to further study the relationship between catalyst surface properties and catalytic performance.In the future,we will regulate the surface structure of the catalyst through various methods to further reveal the influence of the surface properties of the catalyst on the catalytic activity and selectivity,so as to better guide the design,preparation and application of catalysts.