Ingenious p-d orbital hybridization induced by atomic Yb doping for CO₂ reduction to CO

Orbital hybridization plays a crucial role in catalytic processes, yet elucidating its mechanism remains a significant challenge. Here, we have developed a strategy for the formation of Yb-C bond by unconventional p-d orbital hybridization, which induced carbon nitride modified by rare-earth metal element Yb. The optimal sample exhibits catalytic performance 11.2 times greater than that of g-C₃N₄ with N vacancies (NvCN). Yb-C bond and N vacancies reduced the energy barrier and optimized the rate-determining step (*COO + *H → *CO + *OH). Additionally, the intense Yb-C interaction created a specific electrons bridge, which accelerated the transfer rate of electrons on the photocatalytic surface. Next, the CO₂ conversion reaction mechanism was studied by in situ infrared spectroscopy and theoretical calculations, and the unconventional p-d orbital hybridization contributed to the generation of vital intermediate *CO. This study provides a theoretical basis for designing single-atom photocatalysts for the reduction of CO₂.