Dual-selective hydrogen and ethanol sensor for steam reforming systems

The use of micro- and nano-sensors is nowadays becoming more important in order to monitor several aspects of human life and environment. Controlled production of metal oxides nanostructures for gas-sensing applications is therefore crucial to integrate nanosensors to most systems, as they are ideal materials for such utilization. Here, nickel oxide (NiO) polycrystalline nanowires were grown and used to realize sensors that can selectively detect hydrogen and ethanol gas. NiO semiconducting nanowires with polycrystalline structure were grown through an easy, cheap and scalable hydrothermal procedure. Morphology and crystal structure of the NiO nanowires were investigated by energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. The NiO nanostructures were then tested as gas sensors showing very good performance in terms of sensor response (107% for hydrogen, 136% for ethanol), stability, response and recovery times (20 s for hydrogen, 35 for ethanol). Their tunable dual-selectivity to hydrogen and ethanol make them ideal for use in ethanol steam-reforming systems.(C) 2016 Elsevier B.V. All rights reserved.