Low‐Spin W III ‐Triggered Triplet Spin‐Polarized Electron Delocalization of Tungsten Oxide for Photocatalytic Reduction of Uranium

Abstract Solar‐light‐driven photocatalysis is a green and efficient technology to immobilize high‐toxic and radioactive uranium (U). However, a great challenge is to develop photocatalysts with simultaneous elevated conduction band (CB) potential and rapid charge carrier separation rate. Herein, spin‐state engineering in d 0 WO 3 through (110) facet‐confined oxygen vacancies (OVs) is proposed. Anchoring OVs at the symmetry‐broken (110) facets induces low‐spin W III (d 3 ) generation, delocalizing CB electrons and elevating CB by −0.86 V versus NHE due to higher electron occupancy in π antibonding orbitals. Density functional theory (DFT) calculations combined with femtosecond transient absorption spectroscopy (fs‐TAS) reveal that triplet (T)‐dominated spin‐polarized electron delocalization significantly disrupts the charge carrier recombination pathway. Experiments and theoretical calculations confirm the enhanced interfacial charge transfer via O bridging between W 5d and U 5f provides a W 5d → U 5f directional electron transfer channel. Thus, the developed (110)‐WO 2.35 achieves high photocatalytic activity for U(VI) removal from water under simulated solar light, with a reduction efficiency of 98.0% ( C 0 = 10 mg L −1 ) and a reaction rate constant ( k 1 ) of 0.022 min −1 , which is 4.1 times higher than the conventional WO 3 . This work pioneers atomic‐scale spin‐orbital synergy in d 0 photocatalysis, offering a novel strategy for radionuclide remediation.