S-Scheme System of MoS2/Co3O4 Nanocomposites for Enhanced Photocatalytic Hydrogen Evolution and Methyl Violet Dye Removal under Visible Light Irradiation

Abstract

Photocatalytic hydrogen production joined with simultaneous organic compound removal is a potential but challenging approach for both environmental modification and reusable energy generation. In this study, we designed a nanocomposite method for the fabrication of MoS2/Co3O4 heterojunction with an extremely productive photocatalytic capability. The as-fabricated MoS2/Co3O4 nanocomposites displayed greatly enhanced the hydrogen production (3825 μmol/g/h) and methyl violet dye (MV) contaminant removal (apparent kinetic constant of 0.038 min−1) activity. The nanocomposites’ structures had a better specific surface area, numerous active sites, and enhanced the transport ability of charge carriers to promote the photocatalytic activity. The increase in Co3O4 improved the visible-light absorption efficiency and narrowed energy bandgap and served as a highway for charge carriers to facilitate the transfer and separation and inhibit the combination of photoinduced charge carriers. The migration route of the photoexcited charges, the formation pathway, and the function of various reactive oxygen species (such as O2− and •OH) are discussed. The optimized energy band structure and high electron transfer rate of the S-scheme heterojunction nanocomposite promotes the evolution of H2 and the removal of pollutants, which shows an excellent potential in a stable and efficient photocatalytic hydrogen evolution and environment remediation.