Heating Method Effect on SnO Micro-Disks as NO2 Gas Sensor

Mateus G Masteghin,Marcelo O Orlandi,Denis R M Godoi

doi:10.3389/fmats.2019.00171

Mateus G Masteghin, Marcelo O Orlandi + Show 1 more

Open Access

https://doi.org/10.3389/fmats.2019.00171

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Abstract

There is an increasing concern about NOx emission, and many studies have been carried out using metal oxide semiconductors (MOS) aiming its detection. Among the MOS, the SnO micro-disks present a high sensor response and a great selectivity towards NO2. Nevertheless, sensor signal, limit of detection (LOD), and recovery time are related to the experimental setup used to carry on the measurements. Thus, two different heating methods (self-heating and external heating) have been carried out to understand in what manner they change the sensor properties of the SnO micro-disks onto interdigitated electrodes. The external heating method presented higher sensor signal, best LOD, and lower recovery time, mainly due to the lack of a temperature gradient between the SnO disks and the chamber atmosphere. On the other hand, response time was shown to be the same regardless of the method. Briefly, the authors used thermodynamic equations to better understand the temperature effect on the gas-solid interactions occurring between SnO disks and NO2 species.

Highlights

Human activities such as the use of mobile sources and electric power plants are major contributors that generate NO2, which is one of the compounds in the NOx family (Nagase and Funatsu, 1990; Correa, 1993)
Gas sensor devices based on chemo-resistive metal oxide semiconductors (MOSs), (Barsan and Weimar, 2001; Comini et al, 2002; Barsan et al, 2007; Lee, 2009; Wang et al, 2010; Jin et al, 2017) such as SnO2 (Batzill and Diebold, 2005; Ren et al, 2015; Xu et al, 2015; Cheng et al, 2016; Kida et al, 2016; Li et al, 2016), ZnO (Xu et al, 2000; Wan et al, 2004; Li et al, 2017; Morandi et al, 2017), In2O3 (Li et al, 2003; Zhang et al, 2004; Xiao et al, 2017), WO3 (Li et al, 2004; Yang and Guo, 2017), and CuO (Kim and Lee, 2014), are widely used for the detection of toxic and explosive gases (NO2, CO, CH4, H2S, and H2) as well as VOCs (C3H6O, and C2H5OH)
X-ray diffraction (XRD) showed a majority of SnO phase (Litharge-type tetragonal structure), and this result was endorsed by Raman spectroscopy

Summary

Introduction

Human activities such as the use of mobile sources and electric power plants are major contributors that generate NO2, which is one of the compounds in the NOx family (Nagase and Funatsu, 1990; Correa, 1993). This work compares the gas sensor signal of the SnO micro-disks when subjected to distinct experimental arrangements, such as different types of heating.

Results

Conclusion