Effect of Carrier Gas on the Gas Sensing Performance of Co1−2xNixMnxFe2−yCeyO4 Double-Substitution Spinel in Flammable Gases and Volatile Organic Compounds

Abstract

The presence of high concentrations of flammable gases and volatile organic compounds in the atmosphere has been widely reported to be detrimental to human survival. A lot of research effort has been put toward finding an efficient means of quick detection of these gases below their ‘immediately dangerous to life or health’ concentrations. Detecting these gases in an oxygen-deficient environment is a crucial task to consider and has been overlooked. In this research, double-substitution spinel with the chemical formula Co1−2xNixMnxFe2−yCeyO4, where 0 ≤ x = y ≤ 0.3, was prepared via the glycol-thermal technique. The final products, following appropriate substitution, were CoFe2O4 (dried naturally), CoFe2O4 (dried with infrared lamp), Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4, Co0.6Ni0.2Mn0.2Fe1.8Ce0.2O4 and Co0.4Ni0.3Mn0.3Fe1.7Ce0.3O4 spinel ferrites. The X-ray diffractometry (XRD), high-resolution transmission electron micrographs (HRTEM) and X-ray photoelectron spectroscopy (XPS) of the samples confirmed the formation of the spinel. The gas sensing performance of these samples was tested at the operating temperature of 225 °C toward liquefied petroleum gas (LPG), ammonia, ethanol and propanol. The Co0.8Ni0.1Mn0.1Fe1.9Ce0.1O4-based sensor was selective to LPG, with a high response of 116.43 toward 6000 ppm of LPG when helium was used as the carrier gas, 3.35 when dry air was the carrier gas, 4.4 when nitrogen was the carrier gas, but it was not sensitive when argon was used as the carrier gas.