RETRACTED ARTICLE: Colloidal silver diphosphide (AgP(2)) nanocrystals as low overpotential catalysts for CO(2) reduction to tunable syngas

Production of syngas with tunable CO/H(2) ratio from renewable resources is an ideal way to provide a carbon-neutral feedstock for liquid fuel production. Ag is a benchmark electrocatalysts for CO(2)-to-CO conversion but high overpotential limits the efficiency. We synthesize AgP(2) nanocrystals (NCs) with a greater than 3-fold reduction in overpotential for electrochemical CO(2)-to-CO reduction compared to Ag and greatly enhanced stability. Density functional theory calculations reveal a significant energy barrier decrease in the formate intermediate formation step. In situ X-ray absorption spectroscopy (XAS) shows that a maximum Faradaic efficiency is achieved at an average silver valence state of +1.08 in AgP(2) NCs. A photocathode consisting of a n(+)p-Si wafer coated with ultrathin Al(2)O(3) and AgP(2) NCs achieves an onset potential of 0.2 V vs. RHE for CO production and a partial photocurrent density for CO at −0.11 V vs. RHE (j(−0.11, CO)) of −3.2 mA cm(−2).