Synthesis of SnO2 hollow microspheres with core-shell structures through a facile template-free hydrothermal method

SnO2 hollow microspheres with core-shell structures were fabricated by a template-free hydrothermal reaction of a simple aqueous solution containing SnCl4 and NaOH. This process was carried out under mild conditions and required no high-temperature heat treatment. By simply adjusting the molar ratio of SnCl4 to NaOH, hollow microspheres, hollow core-shell microspheres and nanoparticles can be selectively synthesized. The products were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen BET measurements. The as-prepared SnO2 hollow core-shell microspheres present a high Brunauer-Emmett-Teller surface area of 122.4 m2/g and a mesoporous structure. A possible formation mechanism for this kind of core-shell structure was proposed.