Overlayer Au-on-W Near-Surface Alloy for the Selective Electrochemical Reduction of CO_2 to Methanol: Empirical (DEMS) Corroboration of a Computational (DFT) Prediction

It is now widely known from extensive studies [1–3] over the past few decades on the heterogeneous electrochemical reduction of carbon dioxide in aqueous solutions that, across the vast landscape of CO_2-reduction electrocatalysts, copper stands alone as the single metal that can deliver a remarkable variety of products; unpredictably, however, the product distribution does not include methanol [1–5]. The overall energy conversion efficiency of Cu, defined [6] as the ratio of the free energy of the products generated and that consumed in the electrochemical reduction, is only 30 to 40 %, and the overpotential of Cu at benchmark current densities remains unacceptably large, ca. −1.4 V [1, 6]. The diversity of the product distribution also becomes a major hurdle if only one product is coveted. The desire for catalysts that can perform better than Cu, especially in the generation of methanol, a liquid transportation fuel, and feedstock for direct fuel cells, is thus understandable