General strategy for self assembly of mesoporous SnO2 nanospheres and their applications in water purification

Mesoporous SnO2 nanospheres with large surface areas are prepared through a facile hydrothermal route. The as-synthesized product possesses an average diameter of around 40 nm, which is composed of numerous tiny SnO2 nanocrystallites. The possible formation mechanism for the mesoporous SnO2 nanospheres is discussed in detail, and it was found that glucose played a critical role on the morphology of the final products. The photocatalytic properties of the mesoporous SnO2 nanospheres were investigated by photodegrading several organic dyes, such as methylene blue (MB), methyl orange (MO) and Congo red (CR) aqueous solutions under UV irradiation, respectively. Meanwhile, the photodegradation experiments of an MB aqueous solution from three different morphologies of SnO2 (microflowers, core-shell microspheres and mesoporous nanospheres) and ZnO nanosheets were also conducted for the comparison of the photocatalytic activities. Upon comparing the experiments, the mesoporous nanospheres exhibited superior photocatalytic activities, which may be ascribed to their large specific surface area and unique mesoporous structure.