Photosensitization of TiO2 nanosheets with ZnIn2S4 for enhanced visible photocatalytic activity toward hydrogen production

TiO2 nanosheet is a fruitful paradigm for a wide variety of photocatalytic applications due to its char-acteristics of high photoactivity, robust stability, and environmental friendliness. However, its pragmatic utilization for visible light photocatalytic energy conversion still remains challenging owing to the wide bandgap. Herein, a 2D/3D TiO2/ZnIn2S4 nanostructure was purposively constructed via a microwave -assisted synthesis, with ZnIn2S4 functioned as a photosensitizer to overcome the lack of visible light response capacity for TiO2. The optimal TiO2/ZnIn2S4 sample exhibits an excellent photocatalytic H2 evolution activity with a rate of 1167.38 mmol/g/h under visible light illumination, far beyond that of pristine TiO2 nanosheet (6.78 mmol/g/h) and ZnIn2S4 (378.51 mmol/g/h). The enhanced photocatalytic performance can be attributed to synergy effects of the extended visible light response, compatible band alignment, and fast charge carrier separation. The in situ irradiated X-ray photoelectron spectroscopy (XPS) was used to systematically study the transfer behavior of photo-induced electrons; the results highlighted that the flow direction of photoexcited charges is from ZnIn2S4 to TiO2 nanosheets due to the strong interfacial contact. Then both ZnIn2S4 and TiO2 nanosheets can act as the active sites for proton reduction, which therefore boosts the hydrogen production under visible irradiation. This work opens a new venue for the development of flexible photosensitization systems for solar-driven energy conversion.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The study successfully achieved visible light response for TiO2 by constructing a 2D/3D TiO2/ZnIn2S4 nanostructure, significantly improving the photocatalytic hydrogen production performance. The successful construction of this nanostructure provides a new avenue for solar-driven energy conversion.