Electrical promotion of spatially photoinduced charge separation via interfacial-built-in quasi-alloying effect in hierarchical Zn2In2S5/Ti3C2(O, OH)x hybrids toward efficient photocatalytic hydrogen evolution and environmental remediation

Exploring new hybridized catalysts for synergistically promoting the photocatalytic efficiency hold great challenges in solar-to-chemical energy conversion and environmental remediation. Hierarchical Zn2In2S5/Ti3C2(O, OH)x hybrids have been rationally constructed using Ti3C2(O, OH)x as a two-dimensional platform for in situ growth of flower-like Zn2In2S5 microsphere under anaerobically hydrothermal conditions. Upon exposure to visible light, the Zn2In2S5/Ti3C2(O, OH)x hybrids with the Ti3C2(O, OH)x content of 1.5% (by mass) had hydrogen generation yields of 12,983.8 μmol g−1, which was significantly better than that of pure Zn2In2S5. The apparent quantum efficiency reached 8.96% at 420 nm. Furthermore, the photocatalytic tetracycline removal rate was ˜1.25 times higher than that of pure Zn2In2S5, and can be further improved with the increase of temperature in the range of 35–55 °C. Excellent photocatalytic activity originated from the synergistic effects between visible-light-active Zn2In2S5 and conductive Ti3C2(O, OH)x for spatial electrical promotion. The photogenerated-electrons transfer efficiency from Zn2In2S5 to Ti3C2(O, OH)x was 33.0%. In accordance with spectroscopic, electrochemical, and density functional theory studies, we proposed that the interfacial-built-in quasi-alloying effect between ZIS and Ti3C2(O, OH)x culminated in notable charge redistribution, which thereby facilitated the spatial separation and transfer of photogenerated electron-hole pairs. This work revealed the underlying photo-excited charge transfer between metallic compound and semiconductor. Economic Development Board (EDB) Enterprise Singapore Ministry of Education (MOE) The authors gratefully acknowledge the financial support provided by the Singapore Ministry of Education Academic Research Funds Tier 2 (MOE2014-T2-2-074; ARC16/15) and Tier 1 (2015-T1-001-023; RG7/15), the GSK (GlaxoSmithKline) – EDB (Economic Development Board) Trust Fund, and the Joint Singapore-Germany Research Project Fund (SGP-PROG3-019). We also acknowledge funding from the Projects of the National Nature Science Foundation of China (No. 21776066, 51708195). Hou Wang, Yuanmiao Sun and Yan Wu contributed equally to this work.