Room Temperature Ionic Liquids Assisted Green Synthesis of Nanocrystalline Porous SnO2 and Their Gas Sensor Behaviors

Nanocrystalline porous tin dioxide (SnO2) materials have been obtained employing room temperature ionic liquids (1-hexadecyl-3-methylimidazolium bromide, C(16)MimBr) as a template via a green sol-gel method at ambient temperature followed by a suitable thermal treatment. These materials have been thoroughly characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, FTIR, and nitrogen adsorption-desorption. A careful tuning of heat-treatment procedures allowed the preparation of SnO2 functional materials with Brunauer-Emmett-Teller surface areas ranging from 38 to 140 m(2) g(-1), an average pore size between super-micropore (1-2 nm) and mesopore (10 nm) range, and a mean particle size from 3.0 to 10.0 nm. The applications in gas sensors for the nanostructures reveal that the obtained SnO2 Materials exhibit highly sensitive, fast-responding, reproducible, and size selective sensing behaviors. The sensor characteristics were discussed in relation to the architectures of the materials, which disclose that the gas-sensor properties are strongly structure-dependent.