Nitrogen-Doped Mesoporous Carbon Supported Cu-based Binary Metals For Electroreduction Of CO₂

Carbon dioxide is an abundantly potential carbon resource despite of its green house effect.Therefore,the conversion and utilization of carbon dioxide are of great significance.Electrocatalytic reduction of carbon dioxide is an effective method to fix carbon dioxide.Although some progress has been made in electrocatalytic reduction of carbon dioxide,electrocatalysts with facile synthesis strategies and high selectivity are still needed.Cu is a metal electrocatalyst that can generate a large number of hydrocarbons,but its selectivity is poor.Cu-based binary metals have attracted extensive attention due to their ability to stabilize intermediates and improve catalyst selectivity.Nitrogen-doped mesoporous carbon material has large specific surface area and excellent electrical conductivity.The doped nitrogen atom can stabilize the supported metals and improve the adsorption capacity of carbon dioxide.Therefore,in this dissertation,we combine the performance advantages of Cu-based binary metals and NMC as well as the technical advantages of electrochemical method.Nitrogen-doped mesoporous carbon supported Cu-based binary metals materials were prepared and applied to electrocatalytic reduction of carbon dioxide,the specific research contents are as follows:（1）Application of NMC supported CuSb materials（CuSb/NMC）in electrocatalytic reduction of carbon dioxideCuSb/NMC materials were prepared by impregnation method,and were characterized by XRD,XPS,SEM and TEM.It was found that Cu and Sb exists in the form of Cu~0 and Sb~0.And Sb is doped into the crystal lattice of Cu,which makes the CuSb/NMC composites more dispersed than the Cu/NMC.For electrocatalytic reduction of CO₂,CuSb/NMC exhibits better performance than Cu/NMC.CuSb/NMC-2（Cu:5.9 wt%,Sb:0.49 wt%）has the optimal electrocatalytic performance,and the Faraday efficiency of methane（35%）is 7 times that of Cu/NMC.The doping of Sb facilitates the dispersion of metal particles,suppresses their agglomeration and increases the catalytic active sites.The material has good stability and the current density remains stable within 10000 s.（2）Application of NMC supported CuCe materials（CuCe/NMC）in electrocatalytic reduction of carbon dioxideA large number of studies have shown that CeO₂ is rich in oxygen vacancy,which is conducive to the adsorption of CO₂,so CuCe/NMC materials were prepared by impregnation method in this work.XRD,XPS and SEM characterizations show that Cu exists in the form of Cu~0 and Ce exists in the form of CeO₂,and CuCe/NMC materials are more dispersed than Cu_0.5/NMC.The effects of different CuCe molar ratios as well as electrolysis potentials on the electrocatalytic reduction of CO₂ were explored.It was found that Cu_0.5Ce_0.5/NMC（CuCe molar ratio of 5:5）exhibits the best electrocatalytic performance,and the Faradaic efficiency of methane reaches 45%.