COMMUNICATION Selective Promotion of CO₂-­to-­Fuels Conversion by Tuning Catalyst Mesostructure

Abstract

An electrode's performance for catalytic CO₂ conversion to fuels is a complex convolution of surface structure and transport effects. Using well‐defined mesostructured silver inverse opal (Ag‐IO) electrodes, it is demonstrated that mesostructure‐induced transport limitations alone serve to increase the turnover frequency for CO₂ activation per unit area, while simultaneously improving reaction selectivity. The specific activity for catalyzed CO evolution systematically rises by three‐fold and the specific activity for catalyzed H₂ evolution systematically declines by ten‐fold with increasing mesostructural roughness of Ag‐IOs. By exploiting the compounding influence of both of these effects, we demonstrate that mesostructure, rather than surface structure, can be used to tune CO evolution selectivity from less than 5 % to more than 80 %. These results establish electrode mesostructuring as a powerful complementary tool for tuning both catalyst selectivity and efficiency for CO₂ conversion into fuels. Keywords: CO₂ reduction; electrocatalysis; mesoporous materials; mass transport; renewable energy