In-situ reduction of Au(S2O3)23− for efficient recovery of gold with magnetically separable shell-core structured MoS2@Fe3O4 composite

Abstract Magnetic MoS2 could be easily separated from water or solid suspensions. In this work, shell-core structured MoS2@Fe3O4 composite was fabricated through hydrothermal method and used as catalyst for recovering gold-thiosulfate complex ions (Au(S2O3)23−) in aqueous solution. The results suggested that MoS2@Fe3O4 composite could effectively in-situ reduce Au(S2O3)23− to gold particles (Au0) with an extremely high reduction capacity of 1541.1 mg/g; moreover, the gold loaded MoS2@Fe3O4 could be easily collected using a magnetic separator. The mechanism of reducing Au(S2O3)23− to Au0 was ascribed to the photoexcited electrons from MoS2@Fe3O4 composite. More importantly, the incorporation of Fe3O4 could effectively enhance the transferred efficiency of photoexcited electrons and accelerate separation of electrons-holes pairs. With great gold reduction capacity and magnetic recyclability, the MoS2@Fe3O4 composite could be a promising material for recovering gold from leaching solutions.