Metal Nanocatalysts For Carbon Dioxide Electroreduction

Carbon dioxide electroreduction（CO₂ER）is a promising way to curb the excessive CO₂ emission and produce valuable products.Due to the eminent conductivity and proper intermediate bonding,metal catalysts towards CO₂ER have drawn numerous attention.Although much progress has been made,it’s still a great challenge to promote carbon monoxide（CO）production and inhibit hydrogen evolution reaction（HER）.We conducted researches on various metals and their alloys including copper（Cu）,palladium（Pd）,gold（Au）to find their most advantageous site for manipulating the intermediate bonding and boosting CO₂ER performance.Combined with experiments and Density Functional Theory（DFT）calculations,we concluded that specific coordinated metal atoms could effectively adjust the intermediate bonding and thus improve the CO₂ER performance.For instance,Pd atoms with generalized coordination number（GCN）around 5 significantly promote the*COOH adsorption,and thus be beneficial for CO₂ conversion to CO.Therefore,we utilized the abundant edge sites whose GCN around 5 on ultrathin hexagonal Pd nanosheets to promote the*COOH adsorption.In this way,effective CO faradaic efficiency was achieved at pretty low potentials,with 94.3%at-0.5 V.vs RHE.Both morphologies and CO current densities remain stable after an 8 hours test.Besides,defected Au（100）facets with low coordination number were proved to significantly promote the*COOH adsorption and thus promote CO₂ER process,which could reach a CO faradaic efficiency of 90.2%at-0.38 V.vs RHE and a CO current density of 418.60A/g at-0.38 V.vs RHE.In summary,we effectively enhanced the CO₂electroreduction to CO over various metal catalysts and explored the origins of activities.We concluded that some metal atoms with proper low coordination numbers contribute mostly to the enhanced CO₂ER performance,as they could significantly promote the*COOH adsorption and descend the*CO adsorption.To further lower the cost of nanocatalysts,we introduced nonnoble metal Cu to noble metal,which not only but also efficiently utilize the electronic and geometric effects between different metals.Moreover,we synthesized single atom catalysts to keep the above advantages and to make the best use of atomic utilization.Among them,neighbouring effets between Zn/Co monomers make Zn/Co-N-C achieving CO Faradaic Efficiency of 93.2%at-0.5 V.vs RHE.