Absorbent cotton derived mesoporous CeO2 hollow tubule for enhanced detection of p-xylene at low energy consumption

Abstract

Ultra-sensitive detection of flammable and carcinogenic p-xylene gas at relatively low energy consumption through metal oxide-based sensors remains a great challenge due to its high stability. Herein, mesoporous CeO2 hollow microtubules with cubic fluorite structure were simply prepared by immersing absorbent cotton into cerium salt and subsequent calcination. The effect of calcination temperature on the microstructure and gas-sensing performance was also studied. The CeO2-500 hierarchical structure calcinated at 500 °C is composed of cross-linked nanoparticles with small size (12 nm), which possesses relatively large specific surface area (60.8 m2·g−1), well-distributed mesopores (15.0 nm) and abundant oxygen vacancy defects. At a relatively low operating temperature of 133 °C, CeO2-500 sensor shows a fast response to 100 ppm p-xylene (Tres = 5.4 s) and detection limit of 100 ppb, which represents the lowest value in reported CeO2-based sensors. Such excellent gas-sensing performance is highly related to the intrinsic structural properties of mesoporous CeO2-500 hollow microtubule, surface adsorbed oxygen and oxygen vacancy defects caused by Ce3+ ions.