Catalyst – Assisted vapor liquid solid growth of α-Bi2O3 nanowires for acetone and ethanol detection

In this study, conductometric gas sensors based on p-type α-Bi2O3 nanowires for the detection of low concentrations of acetone and ethanol were investigated. Excellent sensing performances in terms of high response, fast kinetics and long-term stability at different humidity levels together with good selectivity were found. The synthesis of α-Bi2O3 nanowires was successfully achieved using a simple Vapor-Liquid-Solid (VLS) method. Nanowires were prepared using different catalysts (Au, Pt and Cu) as seed layers but the highest aspect ratio was obtained using Au. The excellent sensing performances were explained by the extra-sensitization caused by spillover effect of gold nanoparticles on the top of the nanowires. The sensing results showed good selectivity and high response towards low concentrations of acetone and ethanol. In particular, the recorded responses were 6.85, 14.4 and 34.1 towards 10, 20 and 40 ppm of ethanol, respectively, and 0.67, 2.11 and 2.93 towards 4, 6 and 10 ppm of acetone, respectively. Stable response towards low acetone concentrations was observed even after increasing the relative humidity level from 50 % to 90 % @ 20 °C. The results achieved in this work for α-Bi2O3 nanowires demonstrate their promising functionalities in chemical/gas sensing applications.