Highly selective environmental sensors based on flame-spray-made SnO2 nanoparticles

Flame-spray-made SnO2 thick films fabricated by spin coating method were studied for toxic and flammable gas-sensing applications. From physical characterization by X-ray diffraction, Brunauer-Emmett-Teller analysis, scanning and transmission electron microscopy, SnO2 nanoparticles were found to have non-agglomerated spherical, hexagonal, rectangle (3-10 nm), and rod-like (3-5 nm in width and 5-20 nm in length) morphologies with large specific surface area of 141.6 m(2)/g. The sensing films were prepared by spin coating on Al2O3 substrate with interdigitated Au electrode. The sensing films were tested toward some important toxic (NO2, CO, SO2) and flammable (H-2, C2H2) gases. It was found that SnO2 sensing film showed excellent response and selectivity for NO2 at a low operating temperature of 200 degrees C. In addition, the response linearly increased and the response time drastically decreased with increasing gas concentration. Therefore, the spin-coated flame-spray-prepared SnO2 sensor is one of the most promising candidates for highly sensitive and selective detection of noxious NO2 gas. (C) 2012 Elsevier B.V. All rights reserved.