Bryophyllum Pinnatum leaf extract mediated MoS2/ZnO nanocomposite for robust photocatalysis applications

Abstract

One of the primary problems of the twenty-first century is the removal or degradation of organic dyes and antibiotics from water systems since they both contribute significantly to water pollution. To address this issue, molybdenum disulfide and zinc oxide nanocomposite (MoS2/ZnO) were produced by simple, eco-friendly and low cost process using Bryophyllum pinnatum (leaf) phytoextract (BPP) as a reducing as well as capping agent. The prepared BPP-mediated MoS2/ZnO nanocomposite (BP-MoS2/ZnO NC) samples were characterized through various techniques including powder XRD, Rietveld refinement, UV–Vis spectroscopy, FESEM, DLS and FT-IR spectroscopy. The BP-MoS2/ZnO samples were further tested for their use in the sunlight-powered photocatalytic breakdown of methylene blue (MB) and their efficiency to break MB molecules was contrasted with the BPP-mediated ZnO (BP-ZnO), Chemical ZnO (Ch-ZnO) and pure MoS2. The photocatalytic investigation reveals a remarkable enhancement in the photocatalytic activity of pristine ZnO when sensitized with MoS2. These results underscore the synergistic effect achieved by combining ZnO and MoS2. Notably, we found that the optimal catalytic performance is achieved at a Mo atomic percentage of 2 % relative to Zn, emphasizing the importance of precise control for maximizing efficacy. Under sun exposure, 0.5 g/L of BP-MoS2/ZnO resulted in 89.35 % photodegradation of a 20 mg/L MB solution with a rate constant of 0.07537 min-1, which was around 10.42 %, 28.51 %, and 51.86 % greater than BP-ZnO, Ch-ZnO, and pure MoS2, respectively. Further, the efficacy of the BP-MoS2/ZnO NC as solar-driven photocatalysts for removal of pharmaceutical drugs (Amoxicillin & Metronidazole) and textile dyes (Methyl orange) pollutants in sunlight was also investigated. These results show that Bryophyllum extract-mediated MoS2/ZnO is a promising material for solar-based photocatalytic applications.