Hybridization of silicon nanowires with TeO2 branch structures and Pt nanoparticles for highly sensitive and selective toluene sensing

In this study, based on Si NW-TeO2 composites sensitized with Pt nanoparticles (NPs), a novel toluene sensor was fabricated. Dense TeO2 branches formed on the stem of Si NWs, and isolated Pt NPs were dispersed uniformly on the composite surfaces. Several different gases present in exhaled breath (NO2, CO, C6H6, and C7H8) at different concentrations were tested at the optimal working temperature (200 degrees C). To study the role of Pt sensitization on the gas sensing characteristics of the composites, both Si NW-TeO2 and Si NW-TeO2/Pt composites were tested. Pt-loaded composite was more sensitive to toluene than Pt-deficient one. A sensing mechanism was proposed. Our results indicate that the inexpensive, fast, and easy-to-use sensor described here has the potential to be employed as a medical diagnostics tool, as well as an environmental monitoring tool.