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

Abstract

Singlet oxygen (1O2) with electrical neutrality and long lifetime holds great promise in producing high-added-value chemicals via a selective oxidation reaction. However, photocatalytic 1O2 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 (Bi2O2SiO3) with alternating heterogeneous layered structure as a model, it is shown that iodine doping can facilitate the spatial redistributions of bands on alternated [Bi2O2] and [SiO3] layers, which can promote the separation and transfer of photogenerated charge carriers. Meanwhile, the band positions of Bi2O2SiO3 are optimized to match the redox potential of 1O2 generation. Benefiting from these features, iodine-doped Bi2O2SiO3 exhibits efficient 1O2 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 1O2 generation.