Catalytic reduction of CO2 to HCO2− by nanoscale nickel-based bimetallic alloy under atmospheric pressure

[Display omitted] •Catalytic reduction of CO2 to HCOO− was performed under atmospheric pressure.•The average CO2 absorption efficiency was achieved as 41.92%.•The selectivity of HCOO− product reached 53.42% based on LC–MS.•The reaction mechanism for the catalytic reduction of CO2 to HCOO− was analyzed. Carbon dioxide (CO2) was converted into formate (HCO2−) in a catalytic reduction system mainly composed of potassium borohydride (KBH4) and nanoscale bimetallic nickel–copper alloy (NBN–C), in which, the average CO2 conversion efficiency of 41.92% was obtained under the optimal experimental conditions, with a HCO2− selectivity of 53.42%. Various characterization methods were employed to investigate the physicochemical properties of NBN–C and the results indicated that NBN–C was a core-shell mesoporous catalyst with key active sites containing Ni0 and Cu0, at which the catalytic reduction of CO2 took place. The reaction mechanism was proposed based on these characterizations and relevant literatures.