Effect of Ag NPs-decorated carbon nanowalls with integrated Ni-Cr alloy microheater for sensing ammonia and nitrogen dioxide gas

초록

Carbon nanowalls (CNWs), which have high mobility, high surface area and high porosity, generally have high potential as gas sensing materials, but poor gas detection performance has been reported due to low response and recovery. To enhance the sensing performance of a chemiresistive gas sensor based on CNWs, a metallic catalyst and micro heating system have been used. Ag NPs were decorated onto CNWs patterned for fabrication of a gas sensor platform with microheater. Diverse characteristics of functionalized CNWs by Ag NPs were investigated via scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. Ag NPs or clusters were optically observed among a significant number of pores on the surface of CNWs, resulting in change in pore size. Also, a certain evidence of Ag NPs was demonstrated by surface-enhanced Raman scattering (SERS), causing a positive and negative shift in the Raman band of CNWs. In terms of gas-sensing perfor-mance, a greater amount of Ag NPs showed highly improved sensing signal for NH3 and NO2 gas from 25 to 100 ppm compared to pristine conditions. The microheater also improved the poor recovery rate of CNWs. Consequently, the combined gas sensing platform with metallic catalyst and microheating system showed significantly enhanced gas sensing performance.(c) 2022 Published by Elsevier B.V.

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