Charge separation dynamics in In2Se3/ZnO/Au ternary system for enhanced photocatalytic degradation of methylene blue under visible light

Abstract

In this study, carrier dynamics and photocatalytic performance of In2Se3/ZnO/Au-nanoparticle ternary composite is reported. The novel photocatalyst In2Se3/ZnO/Au-nanoparticle was fabricated using the hydrothermal and laser ablation techniques. The structural and physical characteristics have been studied by scanning electron microscopy (SEM), tunneling electron microscopy (TEM), ultraviolet-visible (UV–vis) spectrophotometry, and Raman spectroscopy. The photocatalytic activity of the nanocomposites was estimated through the photocatalytic degradation utilizing organic dye of methylene blue in an aqueous solution. The result suggests that the ternary composite showed better photocatalytic performance compared with the pristine and binary composites. The efficient photocatalytic activity is attributed to the active participation of conduction band of ZnO, large surface area, and excitation of both In2Se3 and Au nanoparticle, and increased electron population in In2Se3. The photocatalytic activities were correlated and explained with the carrier dynamics measured from ultrafast transient absorption spectroscopy. It is found that In2Se3/ZnO/Au system shows the higher adsorption among all systems which indicates that electron transfer to methylene blue is got faster for reduction. The correlation of photocatalytic activities with charge separation dynamic of In2Se3/ZnO/Au-nanoparticle ternary composite provides new direction and understanding to fabricate ternary composite based efficient and high-performance photocatalyst.