High response and selectivity of platinum modified tin oxide porous spheres for nitrogen dioxide gas sensing at low temperature

The Pt modified SnO2 porous spheres for NO2 gas sensor have been synthesized through facile hydrothermal method followed by a chemically reducing process. The porous Pt-SnO2 spheres with the size of 400-700 nm in diameter exhibit a dominant pore size of ca. 15 nm and specific surface area of 36.6 m(2) g(-1), which can provide substantial chemical adsorption sites and abundant channels for the diffusion of NO2 molecules. The SnO2 porous spheres with an optimized loading amount of Pt nanoparticles (0.25 wt%) display superior gas sensing performances including higher response (5770) and selectivity to 5 ppm NO2 gas, as well as shorter response and recovery times (30 s/90 s) than other reported NO2 sensing materials at a lower operating temperature (80 degrees C). The comparison experiments indicate that Pt catalyst loading not only improves the response to NO2 gas and reduces the operating temperature, but also exhibits high selectivity to NO2 gas. (c) 2017 Elsevier B.V. All rights reserved.