Study On The Regulation Of Transition Metal Surface Interface To Improve The Selectivity Of CO₂ Electroreduction

The excessive use of fossil fuels has led to a large emission of greenhouse gas CO₂,which has triggered an increasingly serious greenhouse effect,and the sustainable development of mankind is facing severe challenges.Therefore,recycling the CO₂produced is one of the effective strategies to deal with this problem.Among the many CO₂ conversion technologies,CO₂ reduction driven by renewable electricity can generate high value-added fuels and chemical raw materials under mild reaction conditions,which is a potential CO₂ catalytic conversion technology.In this paper,aiming at the scientific and technical problems of high overpotential,selective and slow reaction kinetics of electrocatalytic CO₂ reduction reaction（CO₂RR）,utilized regulation strategy transition metal surface interface,designed and developed NiNPs/Ni-N-C SACs and Cu O/Sn O₂ heterostructures with low cost,low overpotential,high selectivity and high stability,high selectivity and high stability for the formation of CO and C₂,respecyively.Then,the anode and cathode electrodes of Mg-CO₂ battery are Mg alloy sheet and NiNPs/Ni-N-C SACs,respectively.The output of electricity,the proportion of CO/H₂in syngas,and the yields/crystalline quality of Mg HPO₄can be well regulated by manipulating the operation parameters.The main research contents are as follows:（1）In view of the problem of slow CO₂RR kinetics and slow OER kinetics of CO₂RR anode caused by Ni-N-C SACs,Ni-N-C SACs（NiNPs/Ni-N-C SACs）containing NiNPs were prepared,and a new aqueous Mg-CO₂ battery was assembled with Mg plate as the anode.The experimental results show that the synergistic effect between NiNPs and Ni-Nx sites promotes the dissociation of water and accelerates the formation of*COOH,thereby improving the Faraday efficiency and reaction kinetic efficiency of CO generation,the NiNPs/Ni-N-C SACs catalyst displays a high FE_COof98.12%at-0.573 V_RHE and Tafel slope is 163.68 m V dec^-1.When assembled into a Mg-CO₂ battery,the open-circuit voltage is 1.44 V and the peak power density is 2.91 m W cm^-2.The output of electricity,the proportion of CO/H₂ in syngas,and the yields/crystalline quality of Mg HPO₄can be well regulated by manipulating the operation parameters.This work provides new ideas for improving the catalytic activity of electrocatalytic CO₂RR catalysts and constructing new Mg-CO₂ batteries.（2）Aiming at the unclear relationship between the synergistic effect between Cu and Sn species and the adsorption configuration of electrocatalytic CO₂RR intermediates,Cu O/Sn O₂ catalyst with rich heterogeneous interfaces was prepared.The comprehensive use of in situ characterization and ex situ characterization showed that the Cu O/Sn O₂heterostructure was reconstructed to Cu₂O/Sn O₂at–0.85 V_RHE,and further reduced to–1.05 V_RHE was reconstructed to Cu/Sn O_2-x,the former can generate C₁ products with high selectivity,while the latter can generate C₂ products with high selectivity.In situ raman spectroscopy and theoretical DFT calculations show that the synergistic adsorption of*COOH and*CHOCO on the Cu/Sn O_2-x surface is conducive to the formation of*CO and the reduction of the energy barrier of C-C coupling.This work provides new insights into the potential-structure-selectivity relationship of CO₂RR.