Efficient Recovery of Gold(I) from Thiosulfate Solutions through Photocatalytic Reduction with Mn(II)-Doped MoS2

Abstract

Developing efficient materials for the extraction of gold(I) was pivotal for application of ammoniacal thiosulfate leaching technology. Mn-doped molybdenum disulfide (Mn-MoS2) spheres were fabricated by a facile hydrothermal route for photocatalytic reduction of the gold(I) thiosulfate complex ([Au(S2O3)2]3–) in this work. The experimental results exhibited that [Au(S2O3)2]3– was efficiently recycled in the form of gold nanoparticles by Mn-MoS2. The reduction capacity (936.9 mg/g) and rate (2.74 mg/(g min) in 300 min) was 1.5 and 2.72 times higher than that of MoS2, respectively. The inside photocatalytic reduction mechanism was studied by combining an experimental and first-principles approach. Outstanding reduction performance of [Au(S2O3)2]3– was attributed to the enhanced transfer of photoinduced electrons after Mn doping. In addition, S atoms in the Mn-S bond could well interact with Au(I), which slightly promoted the adsorption of [Au(S2O3)2]3– on Mn-MoS2. The discovery provided a promising strategy for the efficient extraction of gold(I) from thiosulfate leaching solutions.