Nanostructured spinel ZnCo 2O 4 for the detection of LPG

Abstract

Nanostrucutred spinel ZnCo 2O 4 (∼26–30 nm) was synthesized by calcining the mixed precursor (consisting of cobalt hydroxyl carbonate and zinc hydroxyl carbonate) in air at 600 °C for 5 h. The mixed precursor was prepared through a low cost and simple co-precipitation/digestion method. The transformation of the mixed precursor into nanostructured spinel ZnCo 2O 4 upon calcinations was confirmed by X-ray diffraction (XRD) measurement, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM). To demonstrate the potential applicability of ZnCo 2O 4 spinel in the fabrication of gas sensors, its LPG sensing characteristics were systematically investigated. The ZnCo 2O 4 spinel exhibited outstanding gas sensing characteristics such as, higher gas response (∼72–50 ppm LPG gas at 350 °C), response time (∼85–90 s), recovery time (∼75–80 s), excellent repeatability, good selectivity and relatively lower operating temperature (∼350 °C). The experimental results demonstrated that the nanostructured spinel ZnCo 2O 4 is a very promising material for the fabrication of LPG sensors with good sensing characteristics. Plausible LPG sensing mechanism is also discussed.