Ordered mesoporous tin oxide with crystalline pore walls: Preparation and thermal stability

Using long-chain room-temperature ionic liquid (RTIL) 1-hexadecyl-3-methylimidazolium bromide (abbreviated as C16mim+Br−) as the templating agent, ordered mesoporous tin oxide materials with cassiterite-type crystalline walls were synthesized by a thermal treatment. The properties of these materials were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), N2 adsorption/desorption and Fourier transform infrared spectrometer (FT-IR). The results showed that the obtained mesoporous tin oxide with ordered mesoporous structure in short range possessed high thermal stability (up to 973 K) and high specific surface area (ca. 350 m2/g). The mesopore walls were composed of crystalline nanoparticles of tin oxide with size of ca. 2.5 nm. The high thermal stability of such mesoporous tin oxide materials was attributed to the wide interactions between the templating agent C16mim+Br− molecules and tin oxide, that is, electrostatic interaction and hydrogen-bonding between C16mim+Br− molecules and tin oxide, as well as π–π stacking of the imidazolium ring. The synthesized mesoporous tin oxide in this report might be advantageously used as anode materials for lithium–ion batteries, chemical sensors, catalysts and so on.