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

CO 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 OH− at cathode and enriching the bulk OH− to anode are the key
factors for an efficient CO-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 Si atom and OH−. The developed
Cu/SiO2 cathode and Co/SiO2 anode successfully promote cathodic
multi-carbon formation and anodic oxygen evolution, thereby improving the
full cell energy efficiency. Even under high-rate electrolysis at 900 mA
cm −2, the selectivity and energy efficiency of multi-carbon
products remains above 80% and 30%. This achievement highlights the
significance of modulating the dynamic OH⁻ transport at full cell in
enhancing CO electroreduction performance.