Two-dimensional MoS2 nanosheet-modified oxygen defect-rich TiO2 nanoparticles for light emission and photocatalytic applications

Abstract

Improvements in the charge transfer interface and efficient light utilization have proven to be essential parameters for the superior performance of heterostructure-based photocatalysis. In the present study, 2D MoS₂ nanosheet-modified oxygen defect-rich anatase TiO₂ nanostructures were developed by the hydrothermal method. Elemental mapping and transmission electron microscopy studies affirmed the functionalization of 2D MoS₂ nanosheets with TiO₂ nanoparticles. Raman spectroscopy and XRD studies confirmed the formation of the MoS₂–TiO₂ heterojunction. UV-DRS studies exhibited improved visible light absorption and significant bandgap narrowing in TiO₂ nanostructures with the modification of 2D MoS₂ nanosheets. PL results also displayed an improvement in the charge separation and reduction in the recombination rate in MoS₂-modified TiO₂. White light emission PL was achieved through modulation in the defect concentration of TiO₂ with the attachment of MoS₂ nanosheets. MoS₂-modified TiO₂ nanostructures showed remarkable photodegradation nature for methylene blue (MB) dye degradation under sunlight. The most efficient MoS₂-modified TiO₂ decomposed 98.3% of MB, 84.7% of oxytetracycline hydrochloride (OTC-HCl) and 80% of methyl orange (MO) molecule solution in just 12 minutes, 50 minutes and 30 minutes, respectively, under sunlight. The enhanced photolysis performance of MoS₂–TiO₂ nanohybrids can be ascribed to the efficient light utilization and synergistic effects among the MoS₂ and defect-rich TiO₂ nanoparticles.