Immobilized Uranyl Site on Carbon Nitride with Orbital Hybridization for Promoted Charge-Carrier Separation in Photocatalysis.

Photocatalysis suffers from short-lived charge carriers and low photon utilization efficiency. Inspired by the abundant high-n orbitals in uranium, in this work, a CN matrix coupled with an uranyl site (U-CN) with strong orbital hybridization between N 2p and U 6d-5f orbitals was synthesized. The 4.46-fold prolonged photogenerated carriers' lifetime of U-CN compared with that of bare CN contributed to a universally promoted photocatalytic activity for toluene selective oxidation, degradation of Rhodamine B, HO synthesis, and CO reduction in a magnification of 4.77-52.6 times. Notably, the conversion of toluene into benzaldehyde reached 92.5 mmol/g/h with an apparent quantum yield of 16% at 420 nm. Theoretical calculations further reveal that the evolution of uranyl sites not only optimizes the photocatalyst electronic structure but also provides highly reactive sites for electron transfer and subsequent activation of oxygen-containing substrates. The immobilization of uranyl on a carbon nitride photocatalyst with promoted photocatalytic performances unlocks a promising paradigm of the synthesis and application of a heterogeneous uranyl-based photocatalyst.