Influence of Ag Metal Dispersion on the Catalyzed Reduction of CO into Chemical Fuels over Ag-ZrO Catalysts.

Metal/metal oxide catalysts reveal unique CO adsorption and hydrogenation properties in CO electroreduction for the synthesis of chemical fuels. The dispersion of active components on the surface of metal oxide has unique quantum effects, significantly affecting the catalytic activity and selectivity. Catalyst models with 25, 50, and 75% Ag covering on ZrO, denoted as Ag/(ZrO), Ag/(ZrO), and Ag/(ZrO), respectively, were developed and coupled with a detailed investigation of the electronic properties and electroreduction processes from CO into different chemical fuels using density functional theory calculations. The dispersion of Ag can obviously tune the hybridization between the active site of the catalyst and the O atom of the intermediate species CHO derived from the reduction of CO, which can be expected as the key intermediate to lead the reduction path to differentiation of generation of CH and CHOH. The weak hybridization between CHO and Ag/(ZrO) and Ag/(ZrO) favors the further reduction of CHO into CHOH. In stark contrast, the strong hybridization between CHO and Ag/(ZrO) promotes the dissociation of the C-O bond of CHO, thus leading to the generation of CH. Results provide a fundamental understanding of the CO reduction mechanism on the metal/metal oxide surface, favoring novel catalyst rational design and chemical fuel production.