Preparation of zinc cobalt composite microstructures derived from metal-organic-framwork and gas-sensing properties of cyclohexanone

Abstract

Metal-organic-framework(MOF)-derived pure ZnO and ZnO/Co₃O₄ composite microstructures with different ratios are prepared by the sol-vothermal method. The crystalline structure, morphology and chemical composition for each of the prepared micro-structures are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscope (XPS), and surface area analyzer respectively. The Gas sensors based on the as-prepared materials are fabricated and their performances of sensing various gases are investigated. The measurement results show that most of the gas sensors exhibit the highest responses to cyclohexanone gas within the test temperature range, and the composite with an appropriate amount of Co₃O₄ can obviously promote the cyclohexanoe-sensing property of ZnO microstructure. The response values of ZnO/Co₃O₄ composite microstructures to cyclohexanone first increase and then decrease with Co₃O₄ content increasing. The ZnO/Co₃O₄ composite microstructure sensor with a zinc-to-obalt ratio of 1∶0.1 shows that its value of response to cyclohexanone with a volume fraction of 100 × 10^–6 at the optimum working temperature (250 ℃) can arrive at 161, which is 6.4 times higher than that of ZnO microstructure under the same condition. Besides, its response and recovery time are 30 s and 35 s, respectively. This excellent detection performance is attributed mainly to the synergy effect between ZnO and Co₃O₄. The work has an important application value in the high-performance detection of cyclohexanone.