Synthesis of SnO2 nanowires forCO, CH4 and CH3OH gases sensing

Khurram Shehzad,Nazar Abbas Shah,Muhammad Amin,Waqar Adil Syed,Murrawat Abbas

doi:10.1177/1550147718790750

Abstract

Synthesis of one-dimensional nanostructures, such as nanowires, is of vigorous significance for achieving the desired properties and fabricating functional devices. In this work, we report the synthesis of tin oxide (SnO2) nanowires on gold-catalyzed silicon substrate by carbothermal reduction process. SnO2 nanowires were synthesized with SnO2 and graphite powders as the source materials at atmospheric pressure and temperature of 900°C in the ambience of nitrogen (N2) gas. First, the effect of source material ratio SnO2:C on growth of SnO2 nanowires was studied. The structural, morphological and compositional properties of the samples were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. The scanning electron microscopy investigation reveals that uniform dense nanowires of SnO2 (diameter ~127 nm and length ~40 µm) were synthesized with vapour–liquid–solid mechanism. Ultraviolet–visible spectra estimate that the optical band gap of the synthesized SnO2 nanowires was 3.72 eV. Second, the gas sensing performance of synthesized SnO2 nanowires was investigated by testing with carbon monoxide (CO), Methane (CH4) and methanol (CH3OH) gases at different operating temperatures and concentrations. Results indicate that the synthesized SnO2 nanowires are highly promising for gas sensing applications.

Highlights

Synthesis of one-dimensional (1D) nanostructures has attracted increasing courtesy in recent years due to research and practical applications of these novel structures in next-generation devices and sensors.[1,2,3,4,5] Tin oxide (SnO2) is a typical wide-band-gap semiconductor (Eg = 3.6 eV, at 300 K for bulk SnO2)
No other peaks of any element were present in the energy dispersive X-ray (EDX) spectra, which show that the synthesized SnO2 nanowires were quite pure and do not have any other impurity.[27]
The sensor was tested at different temperatures ranging from 100°C to 500°C with an interval of 100°C for all three gases and the sensitivity of synthesized SnO2 nanowires is found to be increased with increase in temperature, and it is optimized in temperature range 390°C–410°C, 290°C–310°C and 390°C–410°C for carbon monoxide (CO), CH4 and CH3OH, respectively

Summary

Introduction

The gas sensing performance of these synthesized SnO2 nanowires is evaluated at different temperatures and concentrations for different chemicals such as CO, CH4 and CH3OH. The gas sensing properties of synthesized SnO2 nanowires were checked using the electrical resistance versus time variation for different chemicals like CO, CH4 and

Results

Conclusion