Novel Z-scheme MoS2/Bi2WO6 heterojunction with highly enhanced photocatalytic activity under visible light irradiation

Abstract

In this study, novel Z-scheme MoS2/Bi2WO6 (MB) heterostructured hierarchical flower-like microspheres were successfully prepared via an in-situ growth method on exfoliated MoS2 nanosheets. Experimental results indicated that the content of MoS2 played a key role in controlling the morphology and photocatalytic activity of MB heterostructures. MB-9 exhibited a highly enhanced photocatalytic activity under visible light irradiation compared to pure MoS2, Bi2WO6 and other MB composites, which can be ascribed to the stable Z-scheme heterostructure, leading to the efficient transfer and the separation of photoinduced electrons and holes. The photocatalytic degradation efficiency of rhodamine B (RhB) can reach 100% within 90 min and almost all of Pseudomonas aeruginosa (P. aeruginosa) can be killed after 60 min by MB-9. In addition, MB-9 displayed a nice stability during the photocatalytic process, which favored a long-term use. Moreover, a possible photocatalytic mechanism was proposed based on the active species trapping experiments and electron spin resonance (ESR) tests, verifying that the photogenerated holes (h+) and ⋅O2− radicals were the dominating active species, which followed the Z-scheme reaction mechanism. It is hoped that this work can provide valuable information on developing novel Z-scheme heterostructures with enhanced photocatalytic activities for potential environmental purification and energy conversion.