AUTHOR=Cai Qing , Wang Fang , Xiang Jianglai , Dan Meng , Yu Shan , Zhou Ying 

TITLE=Layered MoS2 Grown on Anatase TiO2 {001} Promoting Interfacial Electron Transfer to Enhance Photocatalytic Evolution of H2 From H2S

JOURNAL=Frontiers in Environmental Chemistry

VOLUME=1

YEAR=2020

URL=https://www.frontiersin.org/journals/environmental-chemistry/articles/10.3389/fenvc.2020.591645

DOI=10.3389/fenvc.2020.591645

ISSN=2673-4486

ABSTRACT=<p>The treatment of hazardous hydrogen sulfide (H<sub>2</sub>S) via photocatalysis technology has been known as one of the most promising green technologies. Photocatalytic production of hydrogen (H<sub>2</sub>) from H<sub>2</sub>S by two-dimensional (2D) semiconductor materials has gathered great attention owing to its large surface area and high catalytic activity. In this work, layered MoS<sub>2</sub> has been successfully grown on TiO<sub>2</sub> {001} surface to fabricate the 2D MoS<sub>2</sub>/TiO<sub>2</sub> {001} composites for H<sub>2</sub> evolution from H<sub>2</sub>S, which can be confirmed by the X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests. Band structures and UV-Vis spectra provide important evidences that MoS<sub>2</sub> loading can significantly narrow the band gap and broaden the light absorbance into the visible light region. Electron transfer is obviously visualized at the interface of MoS<sub>2</sub>/TiO<sub>2</sub>, resulting in the built-in potential from TiO<sub>2</sub> to MoS<sub>2</sub>, which is determined by the density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) test. Consequently, the photo-induced electrons and holes are accumulated at the sides of TiO<sub>2</sub> and MoS<sub>2</sub> under the illumination, respectively, which largely promote the interfacial electron transfer and prolong the lifetime of photo-generated electrons that participate in the photocatalytic reactions of H<sub>2</sub> evolution from H<sub>2</sub>S. This efficient separation of photo-induced carriers can be further proved by photoluminescence (PL) spectra, photocurrent responses, and electrochemical impedance spectra. As a result, the photocatalytic activity of H<sub>2</sub> evolution is largely increased by 9.4 times compared to the pristine TiO<sub>2</sub>. This study could offer a new and facile way to design highly efficient 2D photocatalysts for the application of H<sub>2</sub>S treatment.</p>