Syntheses of complex sulfides AgCuS and Ag₃CuS₂ from the elements under hydrothermal conditions

Abstract

The hydrothermal technique was applied to the syntheses of ternary metal sulfides, AgCuS and Ag₃CuS₂, using silver, copper, and sulfur powders as starting materials. AgCuS was obtained as a single phase when the starting ratio of Ag:Cu:S was 0.9:1.1:1 in water above 120°C for 10 h except for synthesis condition at 120°C for 60 h and inductively coupled plasma (ICP) analysis revealed that experimental silver and copper contents in products were Ag_0.89Cu_1.10S. At 120°C for 60 h, some unidentified peaks were observed in the powder X-ray diffraction (XRD) pattern and plate crystals of new compound were found in addition to AgCuS particles from the field emission scanning electron microscopy (FE-SEM) image. Pure Ag₃CuS₂ was also prepared by a simple reaction of stoichiometric silver, copper, and sulfur powders above 90°C, and the composition of products was Ag_2.99Cu_1.00S.