Syngas, a gaseous mixture of CO and H2, 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 H2/CO ratios via the electrochemical CO2 reduction reaction (CO2RR) on specifically formulated Au25 and PtAu24 nanoclusters (NCs) with core-atom-controlled selectivities. While CO was predominantly produced from the CO2RR on the Au NCs, H2 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 Au25 NC. In contrast, the energy profiles calculated for the HER indicated that the PtAu24 NCs have nearly thermoneutral binding properties; thus, H2 production is favored over CO formation. Based on the distinctly different catalytic selectivities of Au25 and PtAu24 NCs, controlled syngas production with H2/CO ratios of 1 to 4 was demonstrated at a constant applied potential by simply mixing the Au25 and PtAu24 NCs based on their intrinsic catalytic activities for the production of CO and H2
Bibliographical noteFunding Information:
This work was supported by the Carbon-to-X Project (Grant Nos. 2020M3H7A1096344 and 2021M3H7A1026177) through the National Research Foundation of Korea funded by the Ministry of Science and ICT, Republic of Korea, and the Korea Electric Power Corporation (Grant No. R20XO02-23). DFT calculations were performed using the computational resources in the Korea Institute of Science and Technology Information (Grant No. KSC-2021-CRE-0101).
© 2021 Author(s).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry