Construction of MoS2 nano-heterojunction via ZnS doping for enhancing in-situ photocatalytic reduction of gold thiosulfate complex

Recovery of gold thiosulfate complex ([Au(S2O3)2]3−) from leaching solutions has been recognized as a tough task, which limited the industrial promotion of eco-friendly thiosulfate leaching technique. In this work, MoS2/ZnS nano-heterojunction as a catalyst was proposed for the recovery of [Au(S2O3)2]3− from leaching solution. The results indicated that [Au(S2O3)2]3− could not only be efficiently recovered, but also in-situ reduced into Au0 when MoS2/ZnS nano-heterojunction being used in the leaching solution. Mo0.45Zn0.10S exhibited an extremely high reduction capacity (1120.56 mg/g), which was 4.52 and 1.72 times of ZnS and MoS2, respectively. The great improvement was resulted from the ZnS doping on MoS2, which brought stronger light absorption, higher transferred efficiency and lower recombination of photogenerated electron-hole pairs of MoS2. In addition, the Au0 could completely desorpt from MoS2/ZnS nano-heterojunctions in Na2S solution in less than 4 min, leading MoS2/ZnS nano-heterojunction to have remarkable cycling performances. This work provided a new insight for enhancing the recovery and in-situ reduction of gold thiosulfate complex from leaching solutions.