Surface Enrichment in Gallium‐Indium Liquid Alloys: Applied to CO2 Conversion

Liquid metal alloys can accumulate specific solute metal atoms on their surface, creating distinct quasi‐ordered atomic layers. Such atomic layers can be tuned by varying the alloy composition to form catalytic interfaces suited for multi‐step reactions. Here, the surface enrichment in gallium‐indium alloys is studied and utilized for carbon dioxide (CO2) electrochemical reduction. The results show that adding a small amount of indium (16.8 at%) to gallium leads to a significant indium enrichment of >83 at% on the topmost layer of the alloy. This enrichment dictates the CO2 conversion pathway, leading to 98% faradaic efficiency toward formate at −1.90 V vs reversible hydrogen electrode (RHE). This study produces unprecedented insights into key interfacial processes and lays the foundation for significant further work within the areas of catalysis and liquid metals. Adding 16.8 at% of indium to gallium leads to a significant indium enrichment of >83 at% on the topmost layer of the liquid alloy catalyst. Surface enrichment provides suitable catalytic interfaces for a highly efficient carbon dioxide reduction reaction (CO2RR). The enrichment of indium alters the CO2RRpathway, from carbon monoxide (CO)‐dominated production by gallium to formate‐dominated production by indium.