Ultra-long Zn2SnO4-ZnO microwires based gas sensor for hydrogen detection

Ultra-long Zn2SnO4-ZnO microwires were synthesized by thermal evaporation of the mixture of SnO2, ZnO and C powders. Microstructural characterization by means of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy showed that Zn2SnO4-ZnO microwires with excellent crystallinity were 2.8-3.2 mu m in diameter and 4.0-4.2 mm in length. The maximal length-to-diameter ratio of Zn2SnO4-ZnO microwires is approximately 1500. H-2 sensing properties showed that Zn2SnO4-ZnO microwires exhibited not only excellent reversibility to H-2, but also a good linear relationship between the sensor response and H-2 concentration. The response time and recovery time decreased as the operating temperature increased. The highest sensor response of 9.6 to 1000 ppm H-2 was achieved at an operating temperature of 300 degrees C. The electron depletion theory was used for explaining H-2 sensing mechanism by the chemical adsorption and reaction of H-2 molecules on the surface of Zn2SnO4-ZnO microwires. (C) 2016 Elsevier B.V. All rights reserved.