Green synthesis of MoS2 nanoflowers for efficient degradation of methylene blue and crystal violet dyes under natural sun light conditions

Abstract

Molybdenum sulfide (MoS₂) is one of the most important layered semiconductors. Its importance arises because of its chemical, electrical and optical properties that lead to potential applications in fields such as photocatalysis, electrocatalysis, opto-electronics, etc. Here, we report a simple and novel green hydrothermal synthesis of MoS₂ nanoflowers (NFs) from ammonium molybdenum hydrate and thiourea without using any acids or bases. The resultant MoS₂ NFs have good crystallinity with a lattice spacing of 0.61 nm. The optical bandgap of the MoS₂ NFs was found to be 1.55 eV. Photocatalytic degradation of methylene blue (MB) and crystal violet (CV) dyes with the MoS₂ NFs under sun light irradiation was investigated. The MoS₂ NFs showed excellent photocatalytic activity towards the degradation of MB and CV with almost 100% degradation with vigorous stirring under natural sun light. This is the fastest degradation of MB and CV dyes ever reported. This is faster than any other reaction performed by a photocatalyst under stirring and this is the first report on high degradation of CV by MoS₂ NFs under natural sunlight. In addition to this, the MoS₂ NFs displayed excellent repeatability.