MoS₂ nanosheet incorporated α-Fe₂O₃/ZnO nanocomposite with enhanced photocatalytic dye degradation and hydrogen production ability

Abstract

We have synthesized MoS₂ incorporated α-Fe₂O₃/ZnO nanocomposites by adapting a facile hydrothermal synthesis process. The effect of incorporating ultrasonically exfoliated few-layer MoS₂ nanosheets on the solar-light driven photocatalytic performance of α-Fe₂O₃/ZnO photocatalyst nanocomposites has been demonstrated. Structural, morphological and optical characteristics of the as-synthesized nanomaterials are comprehensively investigated and analyzed by performing Rietveld refinement of powder X-ray diffraction patterns, field emission scanning electron microscopy and UV-visible spectroscopy, respectively. The photoluminescence spectra of the as-prepared nanocomposites elucidate that the recombination of photogenerated electron-hole pairs is highly suppressed due to incorporation of MoS₂ nanosheets. Notably, the ultrasonicated MoS₂ incorporated α-Fe₂O₃/ZnO nanocomposite manifests 91% and 83% efficiency in degradation of rhodamine B dye and antibiotic ciprofloxacin respectively under solar illumination. Active species trapping experiments reveal that the hydroxyl (˙OH) radicals play a significant role in RhB degradation. Likewise the dye degradation efficiency, the amount of hydrogen produced by this nanocomposite <i>via</i> photocatalytic water splitting is also considerably higher as compared to both non-ultrasonicated MoS₂ incorporated α-Fe₂O₃/ZnO and α-Fe₂O₃/ZnO nanocomposites as well as Degussa P25 titania nanoparticles. This indicates the promising potential of the incorporation of ultrasonicated MoS₂ with α-Fe₂O₃/ZnO nanocomposites for the generation of carbon-free hydrogen by water splitting. The substantial increase in the photocatalytic efficiency of α-Fe₂O₃/ZnO after incorporation of ultrasonicated MoS₂ can be attributed to its favorable band structure, large surface to volume ratio, effective segregation and migration of photogenerated electron-hole pairs at the interface of heterojunctions and the plethora of exposed active edge sites provided by the few-layer MoS₂ nanosheets.