Synthesis, structural evolution, and optical properties of SnO2 hollow microspheres with manageable shell thickness

Abstract

SnO₂ hollow (H-SnO₂) microspheres were successfully prepared via a facile one-step synthesis using SiO₂ microspheres as templates and NaOH as a reactive etching agent. To determine the calcination temperature, the thermal reaction of the H-SnO₂ microspheres is investigated by thermogravimetric analysis (TGA). The formation mechanism of the H-SnO₂ microspheres is clearly expounded by the evaluation of morphologies and crystalline structures. Herein, the SiO₂ microspheres are completely etched and the shell thickness could be easily manipulated in the range of 21 to 93 nm. The optical band gaps of the H-SnO₂ microspheres were evaluated by ultraviolet and visible spectroscopy. These H-SnO₂ microspheres using SiO₂ microspheres as templates have an outstanding advantage of manageable shell thickness, which would be extensively applied in nanotherapy, disease diagnosis, and gas sensors.