Interfacial Charge Transfer in MoS/TiO Heterostructured Photocatalysts: The Impact of Crystal Facets and Defects.

One of the most challenging issues in photocatalytic hydrogen evolution is to efficiently separate photocharge carriers. Although MoS loading could effectively improve the photoactivity of TiO, a fundamental understanding of the charge transfer process between TiO and MoS is still lacking. Herein, TiO photocatalysts with different exposed facets were used to construct MoS/TiO heterostructures. XPS, ESR, together with PL measurements evidenced the Type II electron transfer from MoS to {001}-TiO. Differently, electron-rich characteristic of {101}-faceted TiO were beneficial for the direct Z-scheme recombination of electrons in TiO with holes in MoS. This synergetic effect between facet engineering and oxygen vacancies resulted in more than one order of magnitude enhanced hydrogen evolution rate. This finding revealed the elevating mechanism of constructing high-performance MoS/TiO heterojunction based on facet and defect engineering.