Effect of sulfur precursors on hydrothermal growth of MoS2 nanostructures and its visible-light-driven photocatalytic activities

Abstract

The molybdenum disulfide (MoS2) nanostructures such as nanosheets, nanoflowers, nanoparticles, and nanoflakes are promising candidate materials for environmental pollution control. In this work, the effect of sulfur precursors i.e. thioacetamide, thiourea, and elemental sulfur on the morphology of hydrothermally grown MoS2 material was studied followed by their visible-light-driven photocatalytic activities toward methyl orange (MO) dye degradation at ambient conditions. Interestingly under scanning electron microscope (SEM) images, the morphologies of synthesized materials were seen to consist of systematic nanosheets, aggregates, and agglomerates. Raman spectroscopy and XRD studies suggested that the grown materials were composed of primarily 1T-2H mixed phase of MoS2 along with a minor oxide phase of molybdenum. Moreover, photocatalytic MO dye degradation activities exhibited by thioacetamide-grown MoS2 nanostructures were found to be better than those of elemental sulfur and thiourea counterparts. The kinetic rates of degradation towards MO dye by materials synthesized with thioacetamide, elemental sulfur, and thiourea were found to be 0.00804 min−1, 0.00614 min−1, and 0.00531 min−1, respectively. The relatively better photocatalytic activities exhibited by thioacetamide-grown MoS2 material were attributed to its predominant nanosheet morphology and the presence of a greater amount of MoS2 contents. This work will be helpful for a better understanding of morphological control hydrothermal synthesis of MoS2-based materials and their subsequent organic dye degradation activities.