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

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.