High response to nitrogen dioxide derived from antimony peroxide modified tin oxide porous nanocomposites serving as gas sensing material

摘要

The Sb_2O_5 modified SnO_2 porous nanocomposites serving as NO_2 gas sensing material have been successfully synthesized through a facile hydrothermal method followed by a calcination process. The porous Sb_2O_5/SnO_2 nanocomposites display a dominant pore size of ca. 20nm and specific surface area of 37.2 m~2 g~(-1), which can provide large contact area for the chemical adsorption of NO_2 molecules and abundant channels for the import and export of NO_2 gas. Gas sensing tests demonstrated that the as-prepared porous Sb_2O_5/SnO_2 nanocomposites (1 mol% Sb_2O_5) achieved superior sensing performances including high selectivity to NO_2, low optimal operating temperature (ca. 100℃), high response (800-5 ppm NO_2), and short response and recovery times (20s and 70s to 5 ppm NO_2, respectively). Comparing with pure SnO_2 porous structure, the enhanced gas sensing performances of the porous Sb_2O_5/SnO_2 nanocomposites are mainly ascribed to the p-n junctions generated from the hybrid of n-type SnO_2 with p-type Sb_2O_5, which not only improved the response and selectivity to NO_2 gas, but also reduced the operating temperature.