Construction of 2D Layered TiO2@MoS2 Heterostructure for Efficient Adsorption and Photodegradation of Organic Dyes

Published: 2021
Nanotechnology, 32 (33)

Abstract

In this work, heterostructures of coupled TiO2@MoS2 with different phases of MoS2 were synthesized via hydrothermal technique. The prepared materials were thoroughly characterized using various techniques, including XRD, SEM, transmission electron microscopy, Brunauer–Emmet–Teller, XPS, Zeta potential and UV–vis spectroscopy. The optimized nanocomposites were tested for the photocatalytic degradation of methyl Orange (MO) under visible light as well as the adsorption of Rhodamine b (RhB) and methelene blue (MB) dyes. The TiO2@1T/2H-MoS2 heterostructures exhibited a narrow bandgap compared to the other studied nanomaterials. A remarkable photodegradation efficiency of TiO2@1T/2H-MoS2 was observed, which completely degraded 20 ppm of MO after 60 min with high stability over four successive cycles. This can be assigned to the formation of unique heterostructures with aligned energy bands between MoS2 nanosheets and TiO2 nanobelts. The formation of these novel interfaces promoted the electron transfer and increased the separation efficiency of carriers, resulting in high photocatalytic degradation. Furthermore, the adsorption efficiency of TiO2@1T/2H-MoS2 was unique, 20 ppm solutions of RhB and MB were removed after 1 and 2 min, respectively. The superior adsorption performance of the TiO2@1T/2H-MoS2 can be attributed to its high surface area (279.9 m2 g−1) and the rich concentration of active sites. The kinetics and the isothermal analysis revealed that the TiO2@1T/2H MoS2 heterstructures have maximum adsorption capacity of 1200 and 970 mg g−1 for RhB and MB, respectively. This study provides a powerful way for designing an effective photocatalyst and adsorbent TiO2-based nanocomposites for water remediation.