Facile synthesis of ultrafine WO3 nanoparticles for highly sensitive acetoin biomarker gas detection

Facile synthesis of metal oxide semiconductors (MOSs) nanoparticles with ultrafine size is quite promising to improve gas sensing performance due to the large effect of the particle size on the electron depletion layer (EDL), however, which is currently difficult to realize. In this work, we synthesized ultrafine WO₃ nanoparticles of 20 ∼ 30 nm via room-temperature hydrolysis with following annealing and investigated the gas sensing performance of the WO₃ nanoparticles towards acetoin biomarker released by Listeria monocytogenes (LMs). The WO₃ gas sensor displays high response (R_a/R_g = 32.0@5 ppm), excellent selectivity and low detection limit at 140 °C. The ultrafine size of WO₃ comparable to its Debye length can lead to a larger variation of EDL thus a higher sensor response. Our work has provided a facile, low cost and large-scale synthetic route to constructing high-performance acetoin biomarker gas sensors and might contribute to the development for LMs detection.