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(2) with CeO(2) (CeO(2)@WS(2)) as a photoactive heterostructure. In this heterostructure, CeO(2)′s growth within WS(2) layers is achieved through ultrasonicating WS(2) and intercalating CeO(2)′s precursor within the WS(2) interlayers, followed by hydrothermal treatment. Through a set of density functional calculations, we demonstrate that CeO(2) and WS(2) form an interface through a covalent bonding that can be highly stable. The electrochemical impedance spectroscopy (EIS) found that the CeO(2)@WS(2) heterostructure exhibits a remarkably higher conductivity (22.23 mS cm(−2)) compared to either WS(2) and CeO(2), assignable to the interface in CeO(2)@WS(2). Furthermore, in a physically mixed CeO(2)-WS(2) where the interaction between particles is noncovalent, the resistance was significantly higher (0.67 mS cm(−2)), 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(2) and WS(2) is type II. Eventually, the CeO(2)@WS(2) heterostructure indicated 446.7 µmol g (−1) CO(2) generation from photocatalytic oxidation of a volatile organic compound (VOC), formic acid, compared to WS(2) and CeO(2) alone.