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 degrees 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.