A Z-scheme WO3/Bi2MoO6 heterostructure with improved photocatalytic activity: The synergistic effect of heterojunction and oxygen vacancy defects

In our study, a series of WO 3 /Bi 2 MoO 6 heterostructured photocatalysts consisting of Bi 2 MoO 6 nanosheets and WO 3 nanorods were synthesized. Due to the Bi 2 MoO 6 nanosheets with two-dimensional structure, the as-prepared WO 3 /Bi 2 MoO 6 heterostructures had abundant oxygen vacancy defects and high exposure of active Bi 2 MoO 6 (010) facets. Compared with the pure Bi 2 MoO 6 and the oxygen vacancy-poor WO 3 /Bi 2 MoO 6 sample, the WO 3 /Bi 2 MoO 6 heterostructure with WO 3 weight ratios of 6 wt% (denoted as WO/BMO(6)) displayed improved photocatalytic activities in degradation of RhB and OTC under visible-light irradiation. The photoluminescence spectra, photoelectrochemical measurements and DOS analysis illustrated that the desirable photocatalytic performance of the WO/BMO(6) composite was attributed to the synergistic effect of heterojunction interface and oxygen vacancy defects on the efficient charge separation and transfer. Based on the trapping experiments, a Z-scheme charge transfer mechanism was proposed for the WO 3 /Bi 2 MoO 6 heterostructure.