Preparation of AgSnO₂ composite powders by hydrothermal process

Abstract

Silver-tin oxide powders were synthesized by the hydrothermal method with Ag(NH₃)₂⁺ solution and Na₂SnO₃ solution as raw materials and Na₂SO₃ as reductant. The precipitation conditions of Na₂SnO₃ solution and the reduction conditions of Ag(NH₃)₂⁺ were also investigated. The powders prepared were characterized by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and energy spectrum analysis. The results show that pH value of the solution is a key parameter in the formation of Sn(OH)₄ precipitate and the reduction reaction of Ag(NH₃)₂⁺ can release H⁺ ions, which results in synchronous precipitation of Sn(OH)₆²⁻ as Sn(OH)₄. The reduction of Ag(NH₃)₂⁺ and precipitation of Na₂SnO₃ occur simultaneously and the coprecipitation of silver and tin oxide is reached by the hydrothermal method. The silver-tin oxide composite powders have mainly flake shape of about 0.3 μm in thickness and there exists homogeneous distribution of tin oxide and silver in the powder synthesized.

Keywords

silver-tin oxide powder / hydrothermal method / flake structure / coprecipitation