Hidden Mechanism Behind the Roughness‐Enhanced Selectivity of Carbon Monoxide Electrocatalytic Reduction

Abstract

High roughness has been proved to be an effective design strategy for electrocatalyst in many systems. Especially, high selectivity of carbon monoxide reduction (CORR) in competition with the hydrogen evolution reaction has been observed on high roughness electrocatalysts. However, the two well-known mechanisms, i.e., decreasing the energy barrier of CORR and increasing local pH, failed to understand the roughness-enhanced selectivity in a recent experiment. Herein we unravel the hidden mechanism by establishing a comprehensive kinetic model for CORR on catalysts with different roughness factors. We conclude that the roughness-enhanced CORR selectivity is actually kinetic controlled by localelectric-field-directed mass transfer of adsorbed species on the electrode surface. Several ways to optimize CORR selectivity are predicted. Our work highlights the kinetics in electrocatalysis on nanocatalysts, and provides a conceptually new principle for future catalyst design.

Surface Engineering on Commercial Cu Foil for Steering C2H4/CH4 Ratio in CO2 Electroreduction

“…This suggested that the evolution of H 2 was suppressed due to the increased local pH at the nanocavities and the competing C 2 H 4 formation reaction. 36 These trends demonstrated that the 10-cycle Cu foil accelerated C−C coupling rather than the formation of CH 4 during CO 2 RR, meaning that the nanocavities introduced by the CV treatment were beneficial to reduce CO 2 to C 2 H 4 and suppress the generation of CH 4 . This conclusion could be confirmed by the performance on the Cu foils treated with different CV cycles.…”