Synthesis and characterization of Z-scheme based MoS2/ GQD/Ag nanocomposite for degradation of organic pollution

Abstract

The constituent composition of heterojunction composite materials can be changed to effectively segregate photogenerated charge carriers and to significantly advance the process of photocatalytic destruction of resistant pollutants under visible light irradiation. This work presents the hydrothermal synthesis of a novel ternary heterojunction composite, MoS₂/GQD/Ag NPs (MS/GQD/Ag) and its photocatalytic performance in the degradation of organic dyes. In the synthesized material, the Z-scheme heterojunction demonstrated enhanced visible light-driven catalytic activity by effectively separating electrons from holes (e⁻/h⁺) and producing reactive oxygen species. In addition to producing reactive radicals, a variety of surface-bound redox cycles are important in the transmission of photogenerated charge carriers. Rhodamin B (RhB) photocatalytic degradation by MS/GQD/Ag under visible light irradiation was investigated, and results demonstrated 99 % RhB was decomposed using 0.1 g/L of ternary composite during 75 min. Experiments using scavenging techniques verified the concurrent activity of hydroxyl and superoxide radical species in the direction of degradation. The structural stability, recyclability for four cycles, and the pH effect in degradation efficiency of the synthesized photocatalyst illuminate its potential application for the degradation of organic pollutants for water treatment.