WO3 nanoplates for sensitive and selective detections of both acetone and NH3 gases at different operating temperatures

Abstract

WO3 nanoplates with abundant surface chemisorbed oxygen species were prepared by a facile hydrothermal method in the presence of polyvinylpyrrolidone (PVP). The crystal phase, morphology and surface composition of the as-prepared sample were characterized. The gas sensing properties of the WO3 nanoplates were investigated systematically and the gas sensing mechanism was discussed. The results show that effective detections towards both acetone and ammonia gases can be simultaneously realized on the WO3 nanoplates-based sensors at different operating temperatures, which is great meaningful for practical applications. At the high operating temperature of 300 °C, the WO3 nanoplates-based sensor displays a wide response range (1–500 ppm), fast response and recovery (3 s and 7 s), good selectivity and stability towards acetone gas. At the low operating temperature of 140 °C, the WO3 sensor also exhibits a good sensing performance to ammonia gas. The different sensing properties at different temperatures may be due to alteration in active oxygen species on the WO3 surfaces (adsorbed active O− at 300 °C and less active O2− at 140 °C) and distinct difference in bonding energies of acetone and ammonia molecules.