Solvent-free infiltration method for mesoporous SnO2 using mesoporous silica templates

Mesoporous tin oxide (SnO2) materials, exhibiting high surface areas, crystalline frameworks and various mesostructures, were successfully obtained by a facile solvent-free infiltration method from mesoporous silica templates. Various kinds of mesoporous silica materials, such as KIT-6 (bicontinuous 3-D cubic, Ia3d), SBA-15 (2-D hexagonal, p6mm), SBA-16 (3-D cubic with cage-like pores, Im3m) and spherical mesoporous silica (disordered), were utilized as the hard templates. Tin precursor (SnCl2 · 2H2O, m.p. 310–311 K) was infiltrated spontaneously within the mesopores of silica templates by melting the precursor at 353 K without using any solvent. The heat-treatment of SnCl2-infiltrated composite materials at 973 K under static air conditions and subsequent removal of silica templates by using HF result in the successful preparation of mesoporous SnO2 materials. The mesostructures as well as the morphologies of mesoporous SnO2 materials thus obtained were very similar with those of the mesoporous silica templates. The mesoporous SnO2 materials exhibit high surface areas of 84–121 m2/g as well as high pore volumes in the range of 0.22–0.35 cm3/g. The present solvent-free infiltration method is believed to be a simple and facile way for the preparation of mesoporous materials via nano-replication from mesoporous silica templates.