Indium oxide-based Z-scheme hollow core–shell heterostructure with rich sulfur-vacancy for highly efficient light-driven splitting of water to produce clean energy

Crafting inorganic semiconductor heterojunction combined with defect engineering and morphology modulation is a strategic approach to make full use of water splitting products. In this paper, a novel Vs-Zn3In2S6 nanosheets/In2O3 hollow hexagonal prisms Z-scheme heterostructrue (Vs-ZIS6INO) was firstly constructed by oil bath method, in which Zn3In2S6 nanosheets with sulfur vacancy in-situ grew on the surfaces of In2O3 hollow hexagonal prisms to form a hollow core–shell structure. The obtained Vs-ZIS6INO heterostructrue utilized water splitting products for H2 and H2O2 production and possessed much superior activity to pure In2O3 and Vs-Zn3In2S6. Especially, the hydrogen production rate of 30Vs-ZIS6INO under visible light irradiation was 3720.88 μmol g−1h−1, which was 86.88 and 6.36 times than that of Zn3In2S6 and Vs-Zn3In2S6, respectively, while In2O3 did not show any H2 production activity. Meanwhile, 30Vs-ZIS6INO could exhibit a H2O2 production rate of 482.57 μmol g−1h−1 through the dual pathways of indirect type 2e- oxygen reduction (ORR) and water oxidation (WOR) without any sacrifice agents, far exceeding In2O3 (7.34 μmol g−1 h−1) and Vs-Zn3In2S6 (57.68 μmol g−1h−1). The excellent photocatalytic H2 and H2O2 generation activities of Vs-ZIS6INO resulted from the synergistic effects of sulfur vacancy, hollow core–shell structure and Z-scheme heterostructrue between Zn3In2S6 and In2O3, which accelerated the electron delocalization, enhanced the absorption and conversion of solar energy, reduced the carrier diffusion distance and ensured high REDOX ability. This study provided a new idea and reference for constructing novel and highly efficient inorganic semiconductor heterostructure by coordinating vacancy defect and morphology design to adequately utilize water splitting.