LAUSR

Abstract Ultra-long Zn 2 SnO 4 -ZnO microwires were synthesized by thermal evaporation of the mixture of SnO 2 , ZnO and C powders. Microstructural characterization by means of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy showed that Zn 2 SnO 4 -ZnO microwires with excellent crystallinity were 2.8–3.2 μm in diameter and 4.0–4.2 mm in length. The maximal length-to-diameter ratio of Zn 2 SnO 4 -ZnO microwires is approximately 1500. H 2 sensing properties showed that Zn 2 SnO 4 -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 °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 Zn 2 SnO 4 -ZnO microwires.