Asymmetric dual-site engineering of surface [Bi2O2]2+ layers on SrBi2Ta2O9 for efficient photocatalytic toluene oxidation

Selective photocatalytic oxidation offers a sustainable pathway for hydrocarbon valorization but is limited by inert nature of molecular oxygen and sluggish interfacial electron utilization. Aurivillius-type layered oxides, with intrinsic polarization fields, facilitate directional charge migration but suffer from severe electron accumulation at surface Bi 3+ sites, leading to the formation of metallic Bi 0 and catalytic deactivation. Here we demonstrate an asymmetric dual-Bi 3+ -site control strategy by constructing a configuration with S partially filled oxygen vacancies in the surface [Bi 2 O 2 ] 2+ layers of SrBi 2 Ta 2 O 9 . This coupled modulation tailors the surface electronic structure and enables effective regulation of oxygen adsorption and activation, thereby favoring reaction pathways mediated by superoxide radicals. As a result, the optimized catalyst delivers a benzaldehyde yield of 14 mmol g −1 h −1 with 82% selectivity, while retaining 94% of its initial activity after four consecutive 8 h cycles, demonstrating both high efficiency and robust stability of S:SBTO 9–x . This work establishes a general paradigm for steering photogenerated electron dynamics through atomic-level asymmetric site engineering, providing a reasonable approach for designing efficient and durable photocatalysts suitable for selective oxidation reactions.