Structure and texture of self-assembled nanoporous SnO₂

Abstract

Synthesis of nanoporous SnO2 by a surfactant self-assembling sol–gel technique is described in this work. The synthesis was performed at room temperature by employing tin(IV) tetra-tert-amyloxide, Sn (OAmt)4, as the porous SnO2 frame precursor in the presence of the micelles of a cationic surfactant solution of cetyltrimethylammonium bromide (CTAB), which, in turn, acts as the SnO2 particle nanostructure director. The pH of the Sn alkoxide–CTAB mixture was adjusted to a value of 2 with HCl in order to eventually achieve a finely dispersed SnO2 gel structure. The final annealed materials were attained after thermal treatment of the above mentioned SnO2 gel systems between 300 and 500 °C. This annealing procedure burned off different numbers of CTAB micelles and caused some sintering of the substrates depending on the final calcination temperature, thus producing truly mesoporous (cylindrical) SnO2 skeletons of pore sizes 5–9 nm and surface areas between 60 and 100 m2 g−1 as well as some other assorted structural and textural characteristics.