Solvent-free infiltration method for mesoporous SnO 2 using mesoporous silica templates

Abstract

Mesoporous tin oxide (SnO 2) 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, Ia3 d), SBA-15 (2-D hexagonal, p6 mm), SBA-16 (3-D cubic with cage-like pores, Im3 m) and spherical mesoporous silica (disordered), were utilized as the hard templates. Tin precursor (SnCl 2 · 2H 2O, 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 SnCl 2-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 SnO 2 materials. The mesostructures as well as the morphologies of mesoporous SnO 2 materials thus obtained were very similar with those of the mesoporous silica templates. The mesoporous SnO 2 materials exhibit high surface areas of 84–121 m 2/g as well as high pore volumes in the range of 0.22–0.35 cm 3/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.