Enhancement of sensitivity towards triethylamine of WO₃ sensor via oxidant pretreatment

WO₃, due to its intrinsic property as an acidic oxide, is a promising candidate as gas sensing material towards toxic gases such as trimethylamine (TEA). In order to further improve the performance of WO₃-based gas sensors, a preparation method is provided in this study to synthesize nanostructured WO₃ with WS₂ as precursor via in-situ oxidation procedure. During preparation, a chemical oxidation treatment was conducted on WS₂ by immersing it in different oxidizing solutions, respectively, such as KMnO₄, HNO₃ and H₂O₂. Then followed by thermal oxidation treatment at 350 °C, various nanostructured WO₃ were successfully prepared. Based on the characterization results, it was found out that the chemical oxidants had different impact on the morphology and structure of the as-prepared WO₃. Gas sensing properties of the WO₃ sensors were evaluated in the presence of various volatile organic compounds. It was discovered that the WO₃-P sensor with KMnO₄ as oxidizing agent shows great improvement of TEA sensing performance compared to the pristine WO₃ sensor, including higher sensing response, shorter recovery time and enhanced selectivity. The sensitization mechanism of WO₃-P could be attributed to its nano-scale grain size, open structure constructed by nanosheets and more favorable crystal structure.