Microwave-assisted gas-liquid interfacial synthesis of WO3 precursor and nano-WO3 for gas-sensing application

Nanostructured WO3 precursor and WO3 with hole were successfully synthesized via a microwave-assisted gas-liquid interfacial method. The obtained samples were characterized by scanning electron microscope, X-ray diffraction, thermogravimetry/DTA, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy techniques. The characterization results showed that the WO3 precursor was gear-like hexagonal crystal WO3/ester composite and the calcined product was monoclinic crystal WO3. The gas-sensing performance of the as-synthesized materials was also investigated. Both nanostructured WO3 precursor and WO3 with hole have optimal working temperature lower than 100 degrees C, quick response times (<15 s) and good selectivity for xylene detecting. The sensitivity for 100 ppm xylene can reach 32 for WO3 precursor at the optimal working temperature of 30 degrees C and that for the calcined WO3 product can get 113 at its optimal working temperature of 80 degrees C.