NH3 Sensing Performance of Pt-Doped WO3·0.33H2O Microshuttles Induced From Scheelite Leaching Solution

WO3·0.33H2O microshuttles (WMSs) self-assembled by numerous nanorods along the same direction were prepared based on a cheap tungsten-containing metallurgical raw material by combination processes of NaOH leaching and one-step hydrothermal method. The microstructures and gas sensing properties of various concentrations (0, 0.7, 1.0, and 1.3 mol%) of Pt-doped WMSs were investigated to improve their performance. The microstructural characterizations demonstrated that the WMSs assembled by one-dimensional WO3·0.33H2O nanorods were approximately 0.8−1.9 µm in diameter. Such nanorods exhibited a single hexagonal structure with their diameters ranging from 17 to 62 nm. The gas sensing properties indicated that Pt-doped WMSs showed superior gas sensing performance in terms of the sensor response and NH3 selectivity in the operating temperature range of 25−225 oC as compared with pure one, and simultaneously Pt doping could significantly reduce the detection limit of NH3. Especially, 1.0 mol% Pt-doped WMSs exhibited highest response of 28.2 to 1000 ppm NH3 at 175 oC, which was 4 times higher than pure one at 50 oC. The remarkably enhanced gas sensing performance of Pt-doped WMSs to NH3 could be ascribed to the electronic and chemical sensitization mechanisms of noble metal nanoparticles.