Gas Sensing Properties of Ordered Mesoporous SnO₂

Abstract: We report on the synthesis and CO gas-sensing properties of mesoporoustin(IV) oxides (SnO_²). For the synthesis cetyltrimethylammonium bromide (CTABr) wasused as a structure-directing agent; the resulting SnO₂ powders were applied as films tocommercially available sensor substrates by drop coating. Nitrogen physisorption showsspecific surface areas up to 160 m²·g-1 and mean pore diameters of about 4 nm, as verifiedby TEM. The film conductance was measured in dependence on the CO concentration inhumid synthetic air at a constant temperature of 300 °C. The sensors show a high sensitivityat low CO concentrations and turn out to be largely insensitive towards changes in therelative humidity. We compare the materials with commercially available SnO₂-basedsensors.