Ultrasonically-assisted synthesis of CeO 2 within WS 2 interlayers forming type II heterojunction for a VOC photocatalytic oxidation

Here, we investigate the band structure, density of states, photocatalytic activity, and heterojunction mechanism of WS with CeO (CeO @WS ) as a photoactive heterostructure. In this heterostructure, CeO 's growth within WS layers is achieved through ultrasonicating WS and intercalating CeO 's precursor within the WS interlayers, followed by hydrothermal treatment. Through a set of density functional calculations, we demonstrate that CeO and WS form an interface through a covalent bonding that can be highly stable. The electrochemical impedance spectroscopy (EIS) found that the CeO @WS heterostructure exhibits a remarkably higher conductivity (22.23 mS cm ) compared to either WS and CeO , assignable to the interface in CeO @WS . Furthermore, in a physically mixed CeO -WS where the interaction between particles is noncovalent, the resistance was significantly higher (0.67 mS cm ), confirming that the heterostructure in the interface is covalently bonded. In addition, Mott-Schottky and the bandgap measurements through Tauc plots demonstrate that the heterojunction in CeO and WS is type II. Eventually, the CeO @WS heterostructure indicated 446.7 µmol g CO generation from photocatalytic oxidation of a volatile organic compound (VOC), formic acid, compared to WS and CeO alone.