Au nanoparticles enhanced Z-scheme Au-CoFe2O4/MoS2 visible light photocatalyst with magnetic retrievability

Abstract

A novel Au-CoFe2O4/MoS2 photocatalytic composite with high, stable, and remarkable visible light activity was prepared via a sol-gel and hydrothermal route. Au-CoFe2O4/MoS2 composite show improved properties in BET, UV–vis DRS, and PL characterization as compared to Au-CoFe2O4 or CoFe2O4/MoS2. The photocatalytic performance was investigated by the degradation of methyl orange (MO) in aqueous suspension under visible light irradiation. As compared to CoFe2O4/MoS2, the degradation efficiency of MO was improved by nearly 60% in the Au-CoFe2O4/MoS2 composite, which can be attributed to the better electron hole separation over the interface through Au nanoparticles. The existence of Au nanoparticles at the interface between CoFe2O4 and MoS2 provided a preferred route for the Z-scheme transfer of the charge carriers. Due to the room temperature magnetization of CoFe2O4, the photocatalyst composite can be recycled easily and showed very stable efficiency in degradation of MO. The investigation of the degradation mechanism revealed that O2− radicals played the most important role in the photocatalytic reaction, which supported the Z-scheme transfer in the Au-CoFe2O4/MoS2 composite.