Maintaining local alkalinity of CO-electroreduction full cell by silica-confined electrocatalysts in membrane electrode assembly

Carbon monoxide electroreduction in alkaline membrane electrode assembly represents an effective approach to achieve carbon neutrality. However, its performance is currently limited by the insufficient modulation of local alkalinity at a full cell level. In this work, we reveal that confining the in situ generated hydroxide at cathode and enriching the bulk hydroxide to anode are the key factors for an efficient carbon monoxide-electroreduction full cell. We thereby propose a silica-confined strategy for electrocatalyst design to maintain high local alkalinity at both cathode and anode by the strong Lewis acid-base interaction between highly electrophilic silicon atom and hydroxide. The developed copper/silica cathode and cobalt/silica anode successfully promote cathodic multicarbon formation and anodic oxygen evolution, thereby improving the full cell energy efficiency. Even under high-rate electrolysis at 900 milliamperes per square centimeter, the selectivity and energy efficiency of multicarbon products remain above 80 and 30%. This achievement highlights the significance of modulating the dynamic hydroxide transport at full cell in enhancing carbon monoxide electroreduction performance.