Regulating Electronic Coupling Channels via Dual‐Metal Sites in Two‐Dimensional Metal–Organic Framework Nanosheets for Ultrafast U(VI) Photoreduction

Abstract

Uranium removal from water is crucial, yet conventional photocatalysis is limited by carrier recombination and poor charge transfer. Herein, a dual‐site electronic coupling channel modulation strategy is proposed by tuning metal sites in both the porphyrin center and paddlewheel nodes of two‐dimensional porphyrinic metal–organic framework nanosheets (M 2 TCPP(M), M = Ni, Zn, Co). Among them, Ni 2 TCPP(Ni) achieves a uranium removal rate of 19.41 mg g − 1 min −1 under light irradiation without sacrificial agents, outperforming most reported systems. Spectroscopic and electrochemical analyses reveal more efficient charge separation, extended carrier lifetime (3.95 ns), and lower ion diffusion resistance. Density functional theory calculations indicate that rational dual‐site modulation promotes metal–ligand orbital hybridization and interfacial electronic coupling, facilitating electron delocalization and charge migration while suppressing recombination. A relatively homogeneous electrostatic potential distribution further suggests a balanced polarization environment that alleviates localized charge accumulation. Beyond excellent photocatalysis, the material shows promising scalability, with stable performance in a flow‑through system achieving 145 mg g −1 h −1 uranium removal. This work highlights the critical role of dual‑metal‑site synergistic modulation in reconstructing interfacial electronic coupling and charge‑transfer behavior, offering a new electronic structure regulation strategy for designing high‑performance photocatalytic uranium reduction materials.