Au@Ag-Zn thin-films catalysts for selective and stable CO₂ electroreduction

The electrocatalytic reduction of CO-2 (ECO2RR) into high-value products like CO presents a viable strategy for achieving carbon neutrality. While Ag-Zn catalysts have demonstrated high activity for CO-selective electroreduction, their limited stability under electrochemical conditions hinders large-scale applications. To overcome this challenge, Au was incorporated into Ag-Zn to develop an Au@Ag-Zn ternary catalyst. Experimental results confirmed that introducing a small amount of Au significantly enhanced both the catalyst's stability and its CO production efficiency. Among the fabricated catalysts, 5.7 wt percent of Au at Ag-Zn catalyst surface showed the highest CO faradic efficiency 94.2 % at -1 V vs. RHE in 0.1 M KHCO3 aqueous electrolyte with the current density -20.26 mA cm-2 in H-type cell at ambient conditions. Additionally, the Au-decorated Ag-Zn catalyst demonstrated excellent durability of over 12 h, 2.4 times higher than the Ag-Zn catalyst alone. The incorporation of Au on the Ag-Zn surface increases the catalyst's hydrophobicity, helping to prevent CO-2 mass transport limitations while preserving the intrinsic Ag-Zn dendritic structure, thereby enhancing catalyst durability during CO-2 reduction.