Tuning CO2 Reduction over Single Rh Atom on Fe3O4(001) Via Surface Hydroxylation

Searching for the catalytic reductive transformation of carbon oxides (CO, CO₂) into value-added chemicals, has always been of broad interest due to the need to meet global energy demand and to decrease greenhouse gas emission. Single metal atoms are rapidly emerging as a new family of promising catalysts, demonstrating remarkable performance towards hydrogenation, water-gas shift, oxidation and other industrially essential reactions. In this study, we provide mechanistic insights into CO₂ reduction over single Rh atom supported on Fe₃O₄(001) using density functional theory (DFT) calculations. Single Rh atom is determined to be positioned at the under-coordinated octahedral positions of Fe₃O₄ surface. A structural accuracy of surface DFT models is confirmed by simulating the extended X-ray absorption fine structure (EXAFS) and comparing the theoretical spectra against the experimental spectra. Importantly, the level of surface hydroxylation on Fe₃O₄(001) is found to be a key to stabilize the important reaction intermediates to maintain CO₂ reduction cycle.