Enhanced photocatalytic performance of MoS2 modified by AgVO3 from improved generation of reactive oxygen species

In this work, an efficient AgVO3/MoS2 composite photocatalyst was successfully synthesized via a hydrothermal method. The photocatalytic activity of the as-prepared photocatalyst was evaluated by using it for assessing the degradation of different organic pollutants under visible-light irradiation. The composite 3%-AgVO3/MoS2 catalyst demonstrated a significantly enhanced photocatalytic activity compared to the pure compounds (AgVO3 and MoS2). The reason behind the excellent photocatalytic performance was the modification of MoS2 by AgVO3 to facilitate O-2 adsorption/activation. In addition, the composite catalyst facilitates the two-electron oxygen reduction reaction whereby H2O2 is generated on the surface of MoS2 to produce additional reactive oxygen species (ROSs). ESR coupled with the POPHA fluorescence detection method and a free radical capture experiment were used to elucidate the mechanism of formation of the ROSs, including center dot OH, center dot O-2(-) and H2O2. Furthermore, the generation of additional ROSs could accelerate electron consumption, leaving behind more holes for the oxidation of organic pollutants. A possible photocatalytic mechanism of the composite is also discussed. (C) 2018, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.