Evolution in Microstructural Properties of Cetyltrimethylammonium Bromide‐Templated Mesoporous Tin Oxide upon Thermal Crystallization

Abstract

Mesoporous crystalline SnO2 was synthesized using a supermolecule‐templating process, in which cetyltrimethylammonium bromide (CTAB) was introduced into a homogenously peptized tin oxyhydroxide sol, followed by calcination in air. The templated powders were calcined either with or without being subjected to a hexamethyldisilazane (HMDS) pretreatment, and the microstructures were characterized as a function of calcination temperature up to 800°C. Organized mesostructure was initially obtained, and grain growth on calcination was the primary factor that destabilized the mesostructure. Compared with the conventional sol–gel process, the templating process promotes the formation of mesoporosity, enlarges pore volume, and drastically slows grain growth. The HMDS treatment further inhibits grain growth above 400°C. The combination of these processes facilitates formation of fully crystallized mesoporous SnO2 materials with very large surface areas. Fully crystallized mesoporous SnO2 that has a surface area of 220 m2/g has been thus obtained by calcination up to 500°C.