Piezo-Photocatalytic Reduction Of Au(I) By Defect-Rich Mos2 Nanoflowers For Efficient Gold Recovery From A Thiosulfate Solution

To achieve a more efficient gold recovery from a thiosulfate solution, piezo-photocatalytic reduction of Au(I) with defect-rich MoS2 nanoflowers (DR-MoS2 NFs) as a catalyst was proposed in this work. Superior piezoelectric response of DR-MoS2 is detected by a piezoresponse force microscopy (PFM) measurement, revealing the excellent spontaneous polarization of DR-MoS2 under an external force. Ultrafast Au(I) reduction is realized by DR-MoS2 NFs with the aid of ultrasonic treatment under indoor light, which is attributed to the decline of the Schottky barrier in the Au/MoS2 interface and the quick separation of photogenerated carriers induced by the piezoelectric potential. Furthermore, the edge sites and S defects of MoS2 are directly proven to be the active sites for Au(I) reduction through the transmission electron microscopy (TEM) measurement, while the edge sites play a dominant role. This work may promote the development of piezo-photocatalysis and facilitate the substitution of environmentally friendly thiosulfate leaching to cyanidation.