Neighboring effects of single-atom cobalt enable high-performance CO2 photoreduction

Herein, we demonstrate the unique neighboring effect of single-cobalt active sites anchored on BiOCl nanosheets with high CO2 photoreduction performances by combining in situ X-ray photoelectron with in situ infrared spectroscopy. More specifically, single-atom Co sites demonstrate an exceptional electron-enriched feature from adjacent Bi atoms, which facilitates the formation of *CO2-Co and *H2O-Bi species, respectively. Under light irradiation, the photoinduced electron transfer from adjacent Bi atoms to single Co active sites is favorable for the formation *COOH and *CO intermediates, accompanied by the oxidation of H2O molecules into *OH and *OOH species on Bi sites. As a result, these dynamic electronic interactions between single-atom Co and adjacent Bi sites are responsible for a record CO evolution activity of 172.6 mu mol g-1 h-1 under sunlight illumination, which exceeds that of pristine BiOCl by nearly one order of magnitude. These findings provide a fundamental understanding of the intrinsic neighboring effect between single-atom sites and adjacent atoms, which should be crucial and essential for the development of high-performance single-atom catalysts.