Promoting CO₂ Electroreduction to Acetate by an Amine-Terminal, Dendrimer-Functionalized Cu Catalyst

Acetate derived from electrocatalytic CO₂ reduction represents a potential low-carbon synthesis approach. However, the CO₂-to-acetate activity and selectivity are largely inhibited by the low surface coverage of in situ generated *CO, as well as the inefficient ethenone intermediate formation due to the side reaction between CO₂ and alkaline electrolytes. Tuning catalyst microenvironments by chemical modification of the catalyst surface is a potential strategy to enhance CO₂ capture and increase local *CO concentrations, while it also increases the selectivity of side reduction products, such as methane or ethylene. To solve this challenge, herein, we developed a hydrophilic amine-tailed, dendrimer network with enhanced *CO intermediate coverage on Cu catalytic sites while at the same time retaining the in situ generated OH^- as a high local pH environment that favors the ethenone intermediate toward acetate. The optimized amine-network coordinated Cu catalyst (G₃-NH₂/Cu) exhibits one of the highest CO₂-to-acetate Faradaic efficiencies of 47.0% with a partial current density of 202 mA cm^-2 at -0.97 V versus the reversible hydrogen electrode.