Superior acetone sensor based on single-crystalline α-Fe2O3 mesoporous nanospheres via [C12mim][BF4]-assistant synthesis

Abstract

Ionic liquid 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C12mim][BF4]) assisted growth of single-crystalline α-Fe2O3 mesoporous nanospheres via hydrothermal synthetic method was investigated. The structure and morphology of the resultant products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption–desorption techniques. The results indicate that [C12min][BF4] plays an important role in microstructure and morphology controlled synthesis of the α-Fe2O3 nanostructures, which are self-assembled with the primary nanoparticles. The gas sensing properties of such single-crystalline α-Fe2O3 mesoporous nanospheres to some organic compounds such as methanol, ethanol, acetone benzene and methylbenzene were investigated. The sensors based on such mesoporous nanospheres, especially the nanospheres calcined at 300°C, exhibit excellent gas selectivity to acetone at working temperature of 170°C, which could be partially ascribed to appropriate amount of [C12mim][BF4] retention. They can detect acetone down to 0.1ppm with good anti-interefernce of ethanol and humidity, implying their potential application in the detection of breath acetone in type-Ι diabetic patients. The formation process and acetone sensing mechanism of such mesoporous nanospheres are also discussed in detail.