In-situ construction of step-scheme MoS2/Bi4O5Br2 heterojunction with improved photocatalytic activity of Rhodamine B degradation and disinfection

In this paper, a novel Step-scheme MoS2/Bi4O5Br2 heterojunction was fabricated through the in-situ mechanical agitation method and the photocatalytic activity of that was examined by the photocatalytic degradation Rhodamine B (RhB) and inactivation of E.coli under visible light irradiation (λ > 420 nm). The Step-scheme MoS2/Bi4O5Br2 heterojunctions displayed the enhanced photocatalytic ability compared to pure Bi4O5Br2 and MoS2 and the MoS2/Bi4O5Br2-3% (MS/BOB-3) heterojunction exhibited the strongest photocatalytic activity which can completely inactivate the 1 × 107 cfu/mL with 180 min and degrade RhB (10 mg/L) with 24 min visible light irradiation, respectively. The photocatalytic mechanism of the MoS2/Bi4O5Br2 heterojunction is was attributed to the generated active species (h+, ·O2- and ·OH) which can effectively destroy RhB molecular and cell-membrane of bacterial as demonstrated by multiple techniques such as LC-MS and fluorescence stain. Additionally, characterization results disclosed that the transfer pathway of charge carriers of constructed MoS2/Bi4O5Br2 heterojunction followed the Step-scheme channel, which not only facilitated the separation and migration of the photo-generated charge carriers, but also improved the light absorption ability of the samples and resulting in the promoted photocatalytic performance of MoS2/Bi4O5Br2 heterojunction. This work paves a new idea to develop novel bismuth oxyhalide-based photocatalytic system for wastewater purification.