Dopant‐Strengthened S‐Scheme Heterointerfaces in Mo‐TiO ₂ /Sb ₂ S ₃ Nanotubes Enable Built‐In Field‐Driven Charge Channels for Efficient Visible‐Light Mineralization of Aromatic VOCs

ABSTRACT Efficient photocatalytic mineralization of volatile organic compounds (VOCs) is fundamentally constrained by limited visible‐light harvesting, rapid charge recombination, and high kinetic barriers associated with aromatic ring cleavage. Herein, it is reported that a Mo‐doped TiO ₂ /Sb ₂ S ₃ nanotube (Mo‐TiO ₂ /Sb ₂ S ₃ ) S‐scheme heterojunction in which dopant‐induced electronic modulation and interfacial built‐in electric field (BIEF) engineering operate cooperatively to enable directional charge transport and accelerated oxidation kinetics. Mo incorporation increases the TiO ₂ work function and amplifies the Fermi‐level offset relative to Sb ₂ S ₃ , generating a strengthened BIEF that promotes S‐scheme charge transfer while preserving strong redox potentials. Spectroscopic and photoelectrochemical analyses reveal prolonged carrier lifetime, enhanced interfacial charge mobility, and the formation of Ti‐S and Mo‐S covalent pathways that facilitate rapid electron flow and reactive oxygen species (ROS) generation. Density functional theory (DFT) calculations further demonstrates that Mo doping downshifts the d‐band center, strengthens reactant adsorption, and significantly lowers the energy barrier for benzoic acid ring‐opening, the rate‐determining step in toluene mineralization. As a result, the optimized catalyst achieves nearly complete toluene degradation with high CO ₂ selectivity under visible light. This work establishes a synergistic strategy combining dopant‐induced electronic tuning and S‐scheme heterointerface design to overcome kinetic bottlenecks in aromatic VOC mineralization, offering a pathway for advanced air purification.