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

Abstract

Ni single-atom-decorated nitrogen-doped carbon materials (Ni−N x -C) have demonstrated high efficiency in the electrochemical reduction of CO 2 (CO 2 RR) to CO. In this study, Ni−N x -C active sites were embedded within a carbon membrane via an electrospinning and pyrolysis process. The resulting selfsupported carbon membrane hosting Ni−N x -C sites could be directly utilized as an electrode for the CO 2 RR. To enhance the CO 2 RR performance of the carbon membrane, the porous structure of the carbon membrane was fine-tuned by incorporating a poreforming agent. The optimized porous carbon membrane electrode, K 0.66 -Ni-NC, achieved an impressive CO faradaic efficiency (FE CO ) of over 90% within a wide potential range from −0.8 to −1.6 V vs RHE for CO 2 RR. Additionally, it maintained an FE CO of above 90% at −0.8 V vs RHE throughout a 30 h durability test in an Hcell. Further analysis has revealed that the porous structure of the carbon membrane not only facilitates the mass transport of CO 2 but also increases the level of exposure of active sites during the CO 2 RR.