Preparation of Pt-modified In₂O₃ nanobundles with enhanced formaldehyde gas sensing performance

Recently, element doping has become an effective strategy to improve the gas sensing properties of In₂O₃-based materials by adjusting their electronic structures. Herein, Pt-modified In₂O₃ nanobundles, composed of nanofibers, were prepared using a simple hydrothermal method. The dispersion of Pt nanoparticles on the In₂O₃ surface was achieved through an in-situ reduction process. High-resolution TEM images reveal that the In₂O₃ nanofibers possess an average diameter of 30 nm. Brunauer-Emmett-Teller(BET) indicates that the Pt modification can increase the specific surface area. XPS indicates that the introduction of Platinum(Pt) nanoparticles can both increase the oxygen vacancy ratio, and facilitate to trap the electrons, as a result of improving the sensing performance. The gas sensing tests demonstrate that the Pt decorated In₂O₃ nanobundles show excellent sensitivity (5.12 of 100 ppm) and selectivity towards formaldehyde at the optimized temperature of 180 °C. This shows that the decoration of Pt nanoparticles can lower the optimized working temperature and shorten the response/recovery times, of which the enhanced performance can be attributed to electronic and chemical sensitization.