Boosting Electrochemical CO2 Reduction to CO by Regulating the Porous Structure of Carbon Membrane.

Abstract

Ni single-atom-decorated nitrogen-doped carbon materials (Ni-Nx-C) have demonstrated high efficiency in the electrochemical reduction of CO2 (CO2RR) to CO. In this study, Ni-Nx-C active sites were embedded within a carbon membrane via an electrospinning and pyrolysis process. The resulting self-supported carbon membrane hosting Ni-Nx-C sites could be directly utilized as an electrode for the CO2RR. To enhance the CO2RR performance of the carbon membrane, the porous structure of the carbon membrane was fine-tuned by incorporating a pore-forming agent. The optimized porous carbon membrane electrode, K0.66-Ni-NC, achieved an impressive CO faradaic efficiency (FECO) of over 90% within a wide potential range from -0.8 to -1.6 V vs RHE for CO2RR. Additionally, it maintained an FECO of above 90% at -0.8 V vs RHE throughout a 30 h durability test in an H-cell. Further analysis has revealed that the porous structure of the carbon membrane not only facilitates the mass transport of CO2 but also increases the level of exposure of active sites during the CO2RR.