In situ preparation of halogen modified silver nanocatalysts for efficient co-catalysis of CO2 reduction and glycerol oxidation

Electrocatalytic CO 2 reduction (ECR) to valuable feedstocks is considered as one of the most promising CO 2 resource utilization strategies. However, the challenge of balancing high Faradaic efficiency (FE) and large current density ( j ) of reduction products still remains. Herein, halogen anions X − (X = Cl, Br, I) modified Ag (Ag-X) nanocatalysts are constructed by in situ reduction of AgX nanoparticles under ECR conditions, which possess favorable ECR to CO performance. Among them, Ag-Cl exhibited up to 94.12% FE CO and a j CO as high as 15.06 mA cm −2 at −0.75 V vs. RHE in KHCO 3 electrolyte. Particularly, a higher FE CO (98.96%) is obtained in an ionic liquid (IL) electrolyte, and the FE CO could maintain over 90.00% in a wide potential range. Density functional theory (DFT) calculations reveal that the halogen on the Ag nanocatalysts surface reduces the free energy barrier for the formation of essential intermediate *COOH, facilitating the ECR process. Notably, a two-electrode system is employed to generate value-added products, while energy consumption is reduced by 40.5% through coupled anodic glycerol oxidation reaction (GOR) at a current density of 10 mA cm −2 .