Nanowires assembled SnO₂ nanopolyhedrons with enhanced gas sensing properties

Self-assembly of one-dimensional nanoscale building blocks into functional 2-D or 3-D complex superstructures has stimulated a great deal of interest. We report the synthesis and characterization of nanopolyhedrons assembled from ultrathin SnO₂ nanowires based on the sodium dodecyl sulfate (SDS)-assisted hydrothermal process. As-synthesized SnO₂ nanopolyhedrons have uniform diameters around 300 nm and are self-assembled by numerous ultrathin SnO₂ nanowires with diameters of 5-10 nm. The growth mechanism was also studied by investigating the samples synthesized at different reaction time. Thin films of the assembled SnO2 nanopolyhedrons were configured as high performance sensors to detect methanol, ethanol, and acetone, which exhibited 1 ppm sensitivity, very fast response and recovery times (several seconds for different gases with concentrations of 1-200 ppm) to all the target gases and highly selective detection to acetone.