Influence of MoS2 deposition time on the photocatalytic activity of MoS2/ V, N co-doped TiO2 heterostructure thin film in the visible light region

Abstract

Electron-hole separation and a narrow band-gap are essential steps to obtain efficient photocatalysis, towards which the use of co-catalysts or co-doped-TiO2 photocatalysts has become a widely used strategy. In this article, the combination of MoS2 and co-doping of V, N is the goal to achieve high performance photocatalysts. We synthesized MoS2/V, N co-doped TiO2 heterostructure thin film by sol-gel and chemical bath deposition methods. Herein, we investigated the influence of deposition time of MoS2 layer on visible-photocatalytic activity of the obtained samples. The thin films were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and UV–vis spectroscopy techniques. Visible-photocatalytic activity of these samples were evaluated on the removal of methylene blue (MB) under visible light irradiation. The results show that the aforementioned heterostructure thin films have better photocatalytic activities than those of TiO2, MoS2 and V, N co-doped TiO2 counterparts in visible light region. The mechanism for increasing visible-photocatalytic property of the heterostructure thin films is discussed in detail. We find that MoS2/V, N co-doped TiO2 heterostructure thin film at MoS2 deposition time of 45-min shows the highest photocatalytic performance in the visible light region with MB photodegradation rate about 99% for 150 min and the degradation rate constant is 2.06 times higher than that of V and N co-doped TiO2 counterpart.