Ternary zinc oxide-tungsten oxide-MXenes nanocomposite as a high performance material for photocatalytic and photo-electrocatalytic desulfurization of dibenzothiophene

Abstract

It is of prime importance to develop the high-performance photocatalytic materials for desulfurization of organosulfur compounds, which is essential for producing clean diesel fuel and still remains a grand challenge. Tuning the electronic structure through composites of different metal oxides and improving the photocatalytic active sites through morphology regulation in the form of nanostructures are the most popular ways to enhance the photocatalytic performance. Herein, mesoporous ternary composite materials based on WO₃/ZnO/MXene were prepared using a simple physical mixing method. The results showed that the WO₃/ZnO/MXene exhibits a higher photocurrent density (1300 μA/cm²) than ZnO/MXenes (90 μA/cm²). The photocatalytic activity performance of the composite was investigated toward photocatalytic oxidation of dibenzothiophene (DBT) in n-Hexane solution. The effect of key parameters such as temperature, reaction time, DBT concentration, solvent, and voltage in desulfurization of DBT were investigated using the as-prepared composite materials. Under optimum condition, the WO₃/ZnO/MXene revealed up to 82.25 % desulfurization efficiency, which is greater than with ZnO/MXenes materials. Moreover, in comparison with photocatalysis and electrocatalysis approaches, the photo-electrocatalytic method offered better performance and degradation efficiency using WO₃/ZnO/MXenes photoanode with 92.62 % DBT removal during the reaction time. This enhanced activity toward photocatalytic oxidation of DBT can be due to the synergistic effect of multiple metal oxides, increased surface area, presence of mesoporous structure, and uniform distribution of metal oxides in the layered-MXenes structure.