Reconstruction of Interfacial Charge Topology in S‐Scheme Heterojunction for Enhanced CO ₂ Photoreduction

ABSTRACT The S‐scheme heterojunction enables efficient spatial charge separation while preserving strong redox capabilities in photocatalysis. Yet its interfacial charge dynamics remain inherently constrained by fixed band alignment and a built‐in electric field, limiting further performance gains. Here, we demonstrate that plasmonic Au nanoparticles can fundamentally reconstruct, not merely enhance, the interfacial charge topology of an S‐scheme system. By integrating Cs ₃ Bi ₂ Br ₉ quantum dots (CBBQD) with porous BiOCl and decorating with Au, we fabricate a ternary Au/CBBQD/BiOCl heterojunction that achieves a CO evolution rate of 115.4 µmol g ⁻¹ h ⁻¹ , 57.7 times higher than pristine BiOCl and 2.3 times beyond the binary CBBQD/BiOCl S‐scheme counterpart. Combined experimental and density functional theory studies reveal that Au not only serves as a localized surface plasmon resonance (LSPR) hot‐electron injector that redirects photogenerated electrons from CBBQD to the conduction band of BiOCl, thereby shifting the primary CO ₂ reduction site and enabling multi‐site hole utilization, but also lowers the Gibbs free energy barrier of the rate‐limiting ^* CO ₂ → ^* COOH step by 0.36 eV. Our work moves beyond conventional S‐scheme design by establishing plasmonic metals as active architects of interfacial charge flow, offering a general strategy to unlock high‐efficiency CO ₂ photoreduction through deliberate manipulation of electron delivery pathways.