Repositori URV

Identifier: imarina:9156783

Handle: https://hdl.handle.net/20.500.11797/imarina9156783

Authors:
Sharafeldin IGarcia-Rios SAhmed NAlvarado MVilanova XAllam NK

Abstract:
© 2020 Elsevier Ltd. Herein, we report a toxic gas detector based on an array of metal-decorated multiwalled carbon nanotubes (M-MWCNTs) sensors. The room temperature (20 °C) response of the sensors array towards NO2, H2S, NH3, and CO gases was investigated. The MWCNTs were decorated with transition metals, Pt, Ti, Ag, Ru, and Cu to enhance the sensitivity and selectivity of the carbon nanotubes to the toxic gases. The M-MWCNTs powders were deposited on gold electrodes and printed on flexible Kapton sheets to form the sensors array. CO exhibited the lowest resistance change response for all six sensors (five transition metal-decorated MWCNTs sensors and one pristine MWCNTs-based sensor), with the Ag-MWCNTs sensor exhibiting the highest response of 0.047-100 ppm CO. The Ag-MWCNTs also revealed the relatively highest sensitivity of 0.944 upon exposure to 100 ppm NH3. The Cu-MWCNTs sensor showed the highest sensitivity of 1.75 upon exposure to 10 ppm H2S, while the Pt-MWCNTs sensor showed the highest response of 1.96 upon exposure to 10 ppm NO2. A unique response pattern was generated for each gas that can be used for its identification. The experimental results were also compared to our previously reported density functional theory (DFT) calculations, revealing the same order of resistance change, thereby validating the use of DFT as a tool to predict the interaction properties and providing an in-depth understanding of the reducing/oxidizing gas electron transfer mechanisms.