Spatial Band Separation in a Surface Doped Heterolayered Structure for Realizing Efficient Singlet Oxygen Generation.

Abstract

Singlet oxygen (¹ O₂ ) with electrical neutrality and long lifetime holds great promise in producing high-added-value chemicals via a selective oxidation reaction. However, photocatalytic ¹ O₂ generation via the charge-transfer mechanism still suffers from low efficiency due to the mismatched redox capacities and low concentration of photogenerated carriers in confined systems. Herein, by taking bismuth oxysilicate (Bi₂ O₂ SiO₃ ) with alternating heterogeneous layered structure as a model, it is shown that iodine doping can facilitate the spatial redistributions of bands on alternated [Bi₂ O₂ ] and [SiO₃ ] layers, which can promote the separation and transfer of photogenerated charge carriers. Meanwhile, the band positions of Bi₂ O₂ SiO₃ are optimized to match the redox potential of ¹ O₂ generation. Benefiting from these features, iodine-doped Bi₂ O₂ SiO₃ exhibits efficient ¹ O₂ generation with respect to its pristine counterpart, leading to promoted performance in the selective sulfide oxidation reaction. A new strategy is offered here for optimizing charge-transfer-mediated ¹ O₂ generation.