Controlled Syngas Production By Electrocatalytic Co2 Reduction On Formulated Au-25(Sr)(18) And Ptau24(Sr)(18) Nanoclusters

Syngas, a gaseous mixture of CO and H-2, is a critical industrial feedstock for producing bulk chemicals and synthetic fuels, and its production via direct CO2 electroreduction in aqueous media constitutes an important step toward carbon-negative technologies. Herein, we report controlled syngas production with various H-2/CO ratios via the electrochemical CO2 reduction reaction (CO2RR) on specifically formulated Au-25 and PtAu24 nanoclusters (NCs) with core-atom-controlled selectivities. While CO was predominantly produced from the CO2RR on the Au NCs, H-2 production was favored on the PtAu24 NCs. Density functional theory calculations of the free energy profiles for the CO2RR and hydrogen evolution reaction (HER) indicated that the reaction energy for the conversion of CO2 to CO was much lower than that for the HER on the Au-25 NC. In contrast, the energy profiles calculated for the HER indicated that the PtAu24 NCs have nearly thermoneutral binding properties; thus, H-2 production is favored over CO formation. Based on the distinctly different catalytic selectivities of Au-25 and PtAu24 NCs, controlled syngas production with H-2/CO ratios of 1 to 4 was demonstrated at a constant applied potential by simply mixing the Au-25 and PtAu24 NCs based on their intrinsic catalytic activities for the production of CO and H-2. Published under an exclusive license by AIP Publishing.