H<inf>2</inf>S sensor based on SnO<inf>2</inf>nanostructured film prepared by high current heating

Abstract

In this work, SnO2nanostructures prepared by a new high current heating (HCH) route are systematically studied for H2S gas sensing applications. In addition, their gas-sensing properties are compared with those of high-performance SnO2nanoparticles prepared by flame spray pyrolysis (FSP). The SnO2nanostructures were fabricated by gradually heating 30%SnO/70%C wires to a high temperature by passing high current in argon atmosphere. The material properties were characterized by XRD, AFM, SEM, EDS, TEM and XPS. The nanostructures formed around the wire were found to be mainly one-dimensional SnO2nanowires (NWs) (10-100 nm in diameter and tens to hundreds micrometers in length) with high aspect ratios (∼1000) and occasionally hierarchical nanoflowers while zero-dimensional SnO2nanoparticles (5-20 nm) were produced by FSP process. The sensing films were fabricated by spin coating of SnO2powders made by both methods above Al2O3substrates equipped with Au interdigitated electrodes and tested toward H2S (0.2-10 ppm) at 150-350 °C. It was found that the SnO2NWs fabricated by HCH showed high and rapid response to H2S with a high response of ∼380 and a short response time of ∼2.3 s at 10 ppm of H2S and a low optimal temperature of 250°C. A comparison between the two SnO2materials reveals that HCH-made SnO2NWs exhibits better H2S-sensing performances in terms of sensor response, response time and optimal operating temperature than FSP-made SnO2nanoparticles. The superior sensing performance of SnO2NWs could be attributed to better physical properties, particularly higher surface-to-volume ratio and highly reactive surface of single crystal NWs. Therefore, the SnO2NWs sensor prepared by HCH is a promising candidate for sensitive detection of H2S. © 2014 Elsevier B.V.