Phosphorus-substituted atomically dispersed Rh-N3P1 sites for efficient promotion in CO2 hydrogenation towards ethanol production

Ethanol synthesis through CO2 hydrogenation has shown great promise in contributing to carbon neutrality. Herein, we for the first time present the phosphorus-substitution of atomically dispersed Rh-N4 sites for the title reaction. The as-formed Rh-N3P1 sites enable the reaction product notably switching from nearly total methanol (91.3%) towards major ethanol (81.8%) with a high TOF of 420.7 h-1. This outstanding promotion in both ethanol formation and CO2 conversion (69% higher) could be assigned to the donation of electron from P atom effectively weakening C-O bond in CH3OH*, facilitating its cleavage into CH3*, and enabling the coupling between CO* and CH3*. The presence of Rh-P site pair assists C-O bond activation with a longer bond length owing to a strong affinity of P atom to O atom in CH3OH*. This research underscores the importance of tuning the coordination and electronic environment of active metal sites for site pair synergistic catalysis.