Electrochemical Promotion of the CO₂ Reduction Reaction in Ni-BZCYYb-Support Proton-Conducting Ceramic Electrolysis...

This study investigates the electrochemical promotion of the CO₂ reduction reaction (CO₂RR) on Ni-BZCYYb-supported electrodes in proton-conducting electrolysis cells (PCECs). Under anodic polarization, the CH₄ production decreased by 31%, whereas cathodic polarization resulted in a 17% increase. These variations are attributed to changes in the hydrogen atom coverage on the Ni surface induced by electrode polarization. A kinetic model incorporating the charge-transfer reaction at the triple-phase boundary (TPB) and surface reaction mechanisms was developed to describe the CO and CH₄ formation rates. The model captures the relationship between TPB reactions and the average hydrogen coverage on Ni surfaces. It suggests that tuning the electrochemical promotion, via the reduction of the electrolyte and counter electrode resistance or by decreasing the Ni particle size, can effectively modulate the CO₂RR selectivity. These findings offer new insights into electrochemical promotion as a controllable mechanism for enhancing CO₂RR performance, contributing to the development of more sustainable and environmentally friendly catalytic technologies.