Enhancing Electroreduction CO2 to Hydrocarbons via Tandem Electrocatalysis by Incorporation Cu NPs in Boron Imidazolate Frameworks

Abstract

Due to the higher value of deeply-reduced products, electrocatalytic CO₂ reduction reaction (CO₂ RR) to multi-electron-transfer products has received more attention. One attractive strategy is to decouple individual steps within the complicated pathway via multi-component catalysts design in the concept of tandem catalysts. Here, a composite of Cu@BIF-144(Zn) (BIF = boron imidazolate framework) is synthesized by using an anion framework BIF-144(Zn) as host to impregnate Cu²⁺ ions that are further reduced to Cu nanoparticles (NPs) via in situ electrochemical transformation. Due to the microenvironment modulation by functional BH(im)₃ ^- on the pore surfaces, the Cu@BIF-144(Zn) catalyst exhibits a perfect synergetic effect between the BIF-144(Zn) host and the Cu NP guest during CO₂ RR. Electrochemistry results show that Cu@BIF-144(Zn) catalysts can effectively enhance the selectivity and activity for the CO₂ reduction to multi-electron-transfer products, with the maximum FE_CH4 value of 41.8% at -1.6 V and FE_C2H4 value of 12.9% at -1.5 V versus RHE. The Cu@BIF-144(Zn) tandem catalyst with CO-rich microenvironment generated by the Zn catalytic center in the BIF-144(Zn) skeleton enhanced deep reduction on the incorporated Cu NPs for the CO₂ RR to multi-electron-transfer products.

Keywords: Cu nanoparticles; boron imidazolate frameworks; electrocatalytic CO2 reduction reaction; multi-electron-transfer products; tandem catalysts.