High-Current-Density CO2-to-CO Electroreduction on Ag-Alloyed Zn Dendrites at Elevated Pressure

Summary

The electrocatalytic conversion of CO₂ into valuable chemical feedstocks is a highly sought-after route to recycle CO₂ emissions. Among the expected products, CO is a valuable synthon for organic syntheses and fuel generation. Nevertheless, most current electrocatalytic systems do not generate CO at a sufficient rate or purity for its subsequent direct conversion. Herein, we report the rational design of novel and highly active Ag-alloyed Zn dendritic electrodes with remarkable CO₂-to-CO selectivity. Through fine-tuning of the individual electrodeposition parameters, the Ag content, porosity, thickness, and surface area of the electrodes were optimized, leading to a CO₂-to-CO selectivity as high as 91%, which could be sustained above an average of 90% over 40 h. Increase of the CO₂ pressure (up to 9.5 bar) to enhance the CO₂ concentration allowed CO partial current densities as high as –286 mA.cm⁻² to be achieved, setting a new record for predominantly Zn-based electrodes operating in neutral pH.