Realization of low-temperature and selective NO2 sensing of SnO2 nanowires via synergistic effects of Pt decoration and Bi2O3 branching

Metal oxide semiconductors with branched structures, such as branched nanowires (b-NWs), have promising properties for being used in gas sensors. In this work, we synthesized Pt-decorated Bi2O3-branched SnO2 nanowires (NWs). NO2 sensing studies revealed the superior capacity of a Pt-decorated Bi2O3-branched SnO2 NWs gas sensor relative to pristine and branched SnO2 gas sensors, and it worked at near room temperature (50 °C). The increased sensing capacity was related to the synergistic effects of Pt decoration and Bi2O3 branching, particularly the morphology of the gas sensor with branched structures, the promising effects of Pt as a noble metal with good catalytic activity, and the generation of homo- and heterojunctions in the Pt-decorated Bi2O3-branched SnO2 NWs gas sensor. The results obtained in this work are useful for design and development of NO2 gas sensors using a simple strategy, which can be easily extended to various metal oxides.