SnS2 Nanosheets/H‐TiO2 Nanotube Arrays as a Type II Heterojunctioned Photoanode for Photoelectrochemical Water Splitting

• Published in: ChemSusChem 2019-03, Vol.12 (5), p.961-967
• Main Authors: Lin, Jianfei, Liu, Yong, Liu, Yongping, Huang, Chen, Liu, Wenhui, Mi, Xihong, Fan, Dayong, Fan, Fengtao, Lu, Huidan, Chen, Xiaobo
• Format: Article
• Language: English
• Subjects: Electron conductivity; Electrons; heterojunction; Heterojunctions; Hydrogen; hydrogen treatment; Nanosheets; Nanotubes; photoanode; Photoanodes; Photoelectric effect; Photoelectric emission; Separation; SnS2 nanosheets; Substrates; Tin disulfide; TiO2 nanotubes; Titanium dioxide; Water splitting
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.201802691

Improving the separation efficiency of photogenerated electron–hole pairs and the conductivity of electrons to photoanode substrates are critical to achieve high‐performance photoelectrochemical (PEC) water splitting. Here, a SnS2/H‐TiO2/Ti heterojunction photoanode was fabricated with SnS2 nanosheets vertically grown on hydrogen‐treated TiO2 (H‐TiO2) nanotube arrays on a Ti substrate. It showed a significantly enhanced photocurrent of 4.0 mA cm−2 at 1.4 V (vs. reversible hydrogen electrode) under AM 1.5 G illumination, 70 times higher than that of SnS2/TiO2/Ti. Kelvin probe force microscopy measurements indicated that photogenerated electrons could be easily transported through the SnS2/H‐TiO2 interface but not through the SnS2/TiO2 interface. Through hydrogen treatment, defects were created in H‐TiO2 nanotubes to convert type I junctions to type II with SnS2 nanosheets. As a result, a high efficiency of electron–hole separation at the SnS2/H‐TiO2 interface and a high electron conductivity in H‐TiO2 nanotubes were achieved and improved PEC performance. These findings show an effective route towards high‐performance photoelectrodes for water splitting. Exactly your type: A type II heterojunctioned photoanode based on SnS2 nanosheets/hydrogenated TiO2 nanotube arrays (SnS2/H‐TiO2/Ti) shows a significantly enhanced photocurrent of 4.0 mA cm−2 at 1.4 V (vs. RHE), 70 times higher than a type I heterojunctioned photoanode of SnS2 nanosheets/TiO2 nanotube arrays (SnS2/TiO2/Ti). Hydrogenation creates defects in TiO2 nanotubes, improves their electrical conductivity and converts their junctions with SnS2 nanosheets from type I to type II.