Photocatalytic H2 evolution over sulfur vacancy-rich ZnIn2S4 hierarchical microspheres under visible light

Abstract

In this work, the sulfur vacancies were successfully introduced into the ZnIn 2 S 4 (ZIS) lattice through two facile approaches, plasma etching and annealing, for enhancing the photocatalytic performance. The optimized plasma-etched ZIS exhibited an enhanced H 2 generation rate of 706 lmol g -1 h -1 , which was 5 and 1.2 times higher than that of pure ZIS and annealed ZIS, respectively. Theoretical calculation demonstrated that surface S vacancy could arouse the catalytic activity of the adjacent S atoms in inert (001) basal plane, serving as the active site for hydrogen evolution reaction (HER). Although annealing could produce much more S vacancies than the plasma etching, a majority of bulk S vacancies usually acted as charge recombination center to lower the photocatalytic activity. Hence, even plasma-etched ZIS presented poor light absorption capacity, plasma etching showed a better effect on the HER improvement of ZIS than annealing. This work presents a simple and promising pathway for optimization of 3D ZIS photocatalysts to improve photocatalytic hydrogen evolution.

Interface and Defect Engineering of a Hollow TiO2@ZnIn2S4 Heterojunction for Highly Enhanced CO2 Photoreduction Activity

“…After calcination, TiO 2 @ZIS-S also shows a distinct red shift of the absorption edge and enhanced absorption in the visible region, corresponding to the color change of the sample from yellow to green. The UV–vis spectra obtained with a large detection depth reflect the bulk composition of the samples, and the red-shifted absorption edge and greatly strengthened absorption intensity indicate the presence of bulk sulfur vacancies in ZIS-S and TiO 2 @ZIS-S . The generation of sulfur vacancies in TiO 2 @ZIS-S was also demonstrated by elemental analysis using IC.…”

Sulfur Vacancy-Enriched Rhombohedral ZnIn2S4 Nanosheets for Highly Efficient Photocatalytic Overall Water Splitting under Visible Light Irradiation

“…The Nyquist plot of ZnIn 2 S 4 -800 has a smaller arc radius, indicating lower charge transfer resistance. The lifetime of ZnIn 2 S 4 -800 (1.902 ns) is higher than that of ZnIn 2 S 4 (1.506 ns), which suggests that carrier transportation is greatly enhanced. ,− In addition, based on the reported density-functional theory (DFT) results, surface sulfur vacancies that served as electron trapping sites are favorable for suppressing photogenerated charge recombination and enhancing hydrogen evolution reaction (HER) performance. , The synergistic effect mechanism of sulfur vacancies and the crystal phase on photocatalytic activity is shown in Figure S12. The fast carrier transport rate in ZnIn 2 S 4 -800 effectively avoids the surface and bulk carrier recombination, and the abundant sulfur vacancies as active sites can significantly improve the hydrogen production rate.…”

ZnIn2S4 with oxygen atom doping and surface sulfur vacancies for overall water splitting under visible light irradiation

“…The surface sulfur vacancies can be used as electron trapping sites to promote the separation and migration of photogenerated carriers of ZnIn 2 S 4 . 13,22,23 Therefore, the simultaneous introduction of surface sulfur vacancies and oxygen doping in ZnIn 2 S 4 may achieve efficient overall water splitting.…”