W–N–TiO ₂ with positive enough level of valence band maximum and narrowing bandgap for selective aerobic oxidation in visible-light irradiation

Abstract A kind of surface complex (triethylamine and mesoporous W–N–TiO ₂ microspheres with large surface area: 117.5 m ² g ⁻¹ ) catalysis was achieved via visible-light photoredox catalysis. Triethylamine behaves as a true redox mediator due to its highly favorable donating ability. With a lower bandgap (2.43 eV) and higher valence band maximum (2.905 V), W–N–TiO ₂ has the ability to play an active catalytic role yielding excellent conversion and selective oxidation of thioanisole (75.16%) within 12 h under visible-light irradiation. In addition, the reaction and the photocatalyst are applicable to other kinds of thioethers, generally producing high conversion rates and selectivities for the product sulfoxides. The reaction paths were elucidated to reveal that these kinds of surface complexes show characteristics that are likely to be applicable to many aerobic oxidation reactions in future.