Affiliation: | 1. Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, 518055 P. R. China These authors contributed equally to this work.;2. Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026 China These authors contributed equally to this work.;3. Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, 518055 P. R. China;4. Center for High Pressure Science and Technology Advanced Research Pudong, Shanghai, 201203 China;5. Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055 China;6. Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, 117585 Singapore;7. Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230026 China |
Abstract: | Fine-tuning electronic structures of single-atom catalysts (SACs) plays a crucial role in harnessing their catalytic activities, yet challenges remain at a molecular scale in a controlled fashion. By tailoring the structure of graphdiyne (GDY) with electron-withdrawing/-donating groups, we show herein the electronic perturbation of Cu single-atom CO2 reduction catalysts in a molecular way. The elaborately introduced functional groups (−F, −H and −OMe) can regulate the valance state of Cuδ+, which is found to be directly scaled with the selectivity of the electrochemical CO2-to-CH4 conversion. An optimum CH4 Faradaic efficiency of 72.3 % was achieved over the Cu SAC on the F-substituted GDY. In situ spectroscopic studies and theoretical calculations revealed that the positive Cuδ+ centers adjusted by the electron-withdrawing group decrease the pKa of adsorbed H2O, promoting the hydrogenation of intermediates toward the CH4 production. Our strategy paves the way for precise electronic perturbation of SACs toward efficient electrocatalysis. |