Synthesis and characterization of three-dimensional flower-like tin dioxide-based structures

Abstract

Three-dimensional flower-like SnO₂-based structures have been produced by the alkaline hydrothermal treatment of t-SnO₂ powder with no additive and in the presence of aminoterephthalic acid (ATPA). The synthesis products have been characterized by a variety of physicochemical techniques (scanning electron microscopy, transmission electron microscopy, Raman and IR spectroscopies, X-ray diffraction, and others). The results demonstrate that raising the ATPA concentration in the reaction mixture changes the morphology of the materials and leads to the SnO₂ → SnO₂/Sn₃O₄ → Sn₃O₄ phase transformation in the structures through the formation of SnO_x nonstoichiometric tin oxide phases with 1 < x < 2. Hydrothermal treatment of the starting reagents in the presence of ≤75 wt % ATPA leads to the formation of hierarchical structures dominated by a nonstoichiometric tin oxide, which is thermally unstable at t ≥ 500°C. The morphology and phase composition of the synthesized structures have been shown to have a significant effect on the electronic conductivity of the material.