A new solvothermal route to crystalline proustite Ag3AsS3 with photocatalytic properties

A new solvothermal method has been successfully prepared crystalline proustite Ag3AsS3 (1) by the reactions of As2O3, AgNO3 and elemental sulfur in diaminopropane (dap) at 160 °C for 3 days. The crystalline material of 1 was characterized by single crystal X-ray diffraction, powder X-ray diffraction, UV–visible diffuse reflectance spectroscopy, scanning electron microscopy and nonlinear optical determination. The three-dimensional polar framework of 1 is constructed by the linkages of unsymmetrical [AsS3] trigonal pyramids and T-shaped [AgS3] units via bridging S atoms. The absorption edge of 1 is 2.03 eV, exhibiting properties of the semiconductor, and its theoretical band structure has also been studied. Photocatalytic experiments have shown the ability of 1 in the degradation of methylene blue (MB) under visible light (λ > 420 nm).