Two-dimensional ultrathin MoS2 modified hydrogenated TiO2 nanoparticles for superior photocatalytic degradation under simulated sunlight

Abstract

Photocatalysis is an effective technology for degradation of organic contaminants. Herein, we firstly synthesized hydrogenated TiO2 (HT) nanoparticles by calcining P25, and on the basis of HT, two-dimensional ultrathin MoS2/HT binary composites with different component ratios (MHT-20%, MHT-30% and MHT-35%) were controlled prepared. UV–vis diffuse reflectance spectra (DRS) showed that the HT nanoparticles exhibited stronger absorption towards visible light in the range of 550–800 nm compared to P25, and the introduction of two-dimensional ultrathin MoS2 nanosheets further enhanced the visible light absorption ability of MHT composites. Under simulated sunlight irradiation, the removal test of methylene blue (MB) in the present of various photocatalysts indicated that the catalytic performance of HT sample was better than that of P25, and MHT binary composites displayed more excellent photocatalytic performance. A maximum removal efficiency of MB reached 95% within 4 h over MHT-30% photocatalyst. Moreover, the kinetic constant of MHT-30% catalyst is 5.6, 3.6 and 2.5 times as much as that of P25, MoS2 and HT, respectively. In addition, the repeated degradation study and composition analysis of MHT-30% before and after photocatalytic reaction showed that MHT-30% photocatalyst exhibited good stability, and the removal rate of MB still reached 88% in four cycles. The improved and stable photocatalytic performance of MHT-30% can be attributed to band matching and tight interface bonding between MoS2 and HT, which accelerated the electron transfer and broaden the visible-light response range.