TiO2-X mesoporous nanospheres/BiOI nanosheets S-scheme heterostructure for high efficiency, stable and unbiased photocatalytic hydrogen production

The efficiency of hydrogen production via semiconductor photocatalysts is currently limited by poorly light adsorption, rapid recombination of photogenerated carriers, ineffective surface catalytic behavior, and field instability. Herein, a hierarchical S-scheme photocatalyst composite of BiOI nanosheets (NS) with Ti3+ self doped black TiO2-X mesoporous nanospheres (MS) was prepared, from which we observed an improve light utilization, as well as the accelerated separation and migration of photogenerated carriers. Furthermore, the optimized TiO2-X/BiOI heterostructure exhibited a robust H-2 evolution rate of 794.28 mu mol g(-1)h(-1), which was approximately 9.2 and 3 times that of pure BiOI NS and TiO2 MS, respectively. The photocatalytic mechanism of S-scheme heterostructure between black TiO2-X and BiOI was proposed by combining upconversion spectrum, low temperature photoluminescence spectrum and theoretical calculations. This work provides not only a facile synthetic method to prepare the heterojunction structures with high catalytic activity, but also establishes a platform for future materials-by-design with S-scheme energy band structures.

Automated summary

In this study, a hierarchical S-scheme photocatalyst composite was prepared, which achieved efficient hydrogen production through an optimized heterostructure.