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

• Main Authors: W. Nakla, A. Wisitsora-At, A. Tuantranont, P. Singjai, S. Phanichphant, C. Liewhiran
• Format: Journal
• Published: 2018
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84905020142&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/45511
• Institution: Chiang Mai University

In this work, SnO 2 nanostructures prepared by a new high current heating (HCH) route are systematically studied for H 2 S gas sensing applications. In addition, their gas-sensing properties are compared with those of high-performance SnO 2 nanoparticles prepared by flame spray pyrolysis (FSP). The SnO 2 nanostructures 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 SnO 2 nanowires (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 SnO 2 nanoparticles (5-20 nm) were produced by FSP process. The sensing films were fabricated by spin coating of SnO 2 powders made by both methods above Al 2 O 3 substrates equipped with Au interdigitated electrodes and tested toward H 2 S (0.2-10 ppm) at 150-350 °C. It was found that the SnO 2 NWs fabricated by HCH showed high and rapid response to H 2 S with a high response of ∼380 and a short response time of ∼2.3 s at 10 ppm of H 2 S and a low optimal temperature of 250°C. A comparison between the two SnO 2 materials reveals that HCH-made SnO 2 NWs exhibits better H 2 S-sensing performances in terms of sensor response, response time and optimal operating temperature than FSP-made SnO 2 nanoparticles. The superior sensing performance of SnO 2 NWs could be attributed to better physical properties, particularly higher surface-to-volume ratio and highly reactive surface of single crystal NWs. Therefore, the SnO 2 NWs sensor prepared by HCH is a promising candidate for sensitive detection of H 2 S. © 2014 Elsevier B.V.