Construction of 2D layered TiO 2 @MoS 2 heterostructure for efficient adsorption and photodegradation of organic dyes

In this work, heterostructures of coupled TiO 2 @MoS 2 with different phases of MoS 2 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 TiO 2 @1T/2H-MoS 2 heterostructures exhibited a narrow bandgap compared to the other studied nanomaterials. A remarkable photodegradation efficiency of TiO 2 @1T/2H-MoS 2 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 MoS 2 nanosheets and TiO 2 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 TiO 2 @1T/2H-MoS 2 was unique, 20 ppm solutions of RhB and MB were removed after 1 and 2 min, respectively. The superior adsorption performance of the TiO 2 @1T/2H-MoS 2 can be attributed to its high surface area (279.9 m 2 g −1 ) and the rich concentration of active sites. The kinetics and the isothermal analysis revealed that the TiO 2 @1T/2H MoS 2 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 TiO 2 -based nanocomposites for water remediation.