TiO2-x-MoS2 heterostructure: A study of kinetic, thermodynamic, and scavenging agents' effects in photodegradation

Numerous applications for photocatalysis exist in the energy and environmental sectors. In this study, a heterojunction system comprising oxygen vacancies-mediated TiO2 nanorods (TiO2-x) modified with MoS2 nanosheets (TiO2-x-MoS2) was prepared using the hydrothermal method. The photocatalytic activity of TiO2-x-MoS2 heterostructure is about 3 times higher than that of pure TiO2. The heterostructure significantly improved the photoinduced charge carrier separation efficiency, resulting in an increase in active species including (OH)-O-center dot, O2(center dot)-, and h+. Additionally, the Langmuir-Hinshelwood (L-H) model was employed to model kinetic and equilibrium data. The results of scavenging studies indicated that the photocatalytic process heavily relies on superoxide radicals. Additionally, the sensitivity of photocatalytic rates to temperature through kinetic studies based on Arrhenius and transition state models was investigated, which yielded an activation energy of 23.01 kJ/mol for the process. A positive activation entropy (Delta S = +0.017 kJ/mol) was obtained, along with positive Delta H and Delta G values, for the Rhodamine B photodegradation. This work underscores the critical role of oxygen vacancies and heterostructures in advancing wastewater treatment approaches.