Synthesis of 3D-MoS2 nanoflowers with tunable surface area for the application in photocatalysis and SERS based sensing

Nanostructured two-dimensional transition metal dichalcogenides (2D-TMDCs) have been attracting great attention in the field of environmental remediation and sensing due to their high surface area and layer dependent optical and structural properties. Surface area dependent performance of MoS2 nanostructures is one of the important aspects which need to be explored for various environmental applications. In this work, MoS2 nanoflowers with tunable surface area (5–20 m2/g) were prepared by the facile hydrothermal method and their surface area dependent SERS and photodegradation activity were explored. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) studies assure the growth of MoS2 nanoflowers by the assembly of 2D-MoS2 nanosheets. MoS2 nanoflowers exhibit excellent sunlight-induced photocatalytic activity towards the degradation of methylene blue, methyl orange, rhodamine 6G and oxytetracycline hydrochloride molecules. We report that a very low amount (0.025 mg) of MoS2 nanoflowers (20 m2/g) can tremendously decompose 10 μM of MB, MO and R6G dye molecules in just 12 min, 30 min and 45 min respectively and 0.5 mg/10 mL OTC-HCl molecule in 60 min under sunlight which has not been reported yet. MoS2 nanoflowers based substrates show the remarkable SERS based detection towards the rhodamine B (RhB) molecule. Tunability in the SERS for the account of different surface areas poses by the different MoS2 sample has been well explored. Charge transfer mechanism for ultrafast SERS detection and enhanced photodegradation activity has been proposed and explained precisely.