Multi-Walled Carbon Nanotubes Decorated with Silver Nanoparticles for Acetone Gas Sensing at Room Temperature

Abstract

Multi-walled carbon nanotubes (MWCNTs) without and with adsorbed silver nanoparticles (Ag-NPs), are used to detect acetone vapour. MWCNTs are grown on SiO2/Si substrates and silver (Ag) nanoparticles (NPs) are deposited onto some of these MWCNTs using electron beam evaporation method. The sensitivity of CNT based sensors (with and without NPs) increases with the concentration of acetone vapour (50 ppm to 800 ppm) while a substantial rise in sensitivity is obtained from MWCNTs with Ag NPs. Band diagrams of the MWCNTs, with and without NPs, are analyzed to understand the gas molecules adsorption phenomena. This study is the first to establish that such sensors can operate at 27 °C rather than the 180 °C–450 °C used elsewhere, thus offering significant advantages over existing methods. To investigate the sensors’ dependability, they’re exposed to three cycles of 50 ppm acetone gas. These tests show that the devices’ responses remain unchanged, indicating their reliability. The effects of humidity upon MWCNT acetone sensors within 100 ppm of acetone vapour are also studied and improved performance towards stability and response/recovery is observed for the sensors with Ag-NPs. Furthermore, higher selectivity is observed for the Ag-coated sensors for acetone against various target gases (acetone, ethanol, NO2, ammonia, and acetone with water).

Recent Advances in Silver Nanostructured Substrates for Plasmonic Sensors

“…The optical nonlinearities exhibited by Ag/MWCNTs can be attributed to the saturable absorption regarding the absorption band associated with the SPR of AgNPs [ 119 ]. In another report, MWCNTs decorated with AgNPs were demonstrated to improve acetone gas-sensing at room temperature using the resistive sensing method [ 120 ]. Some other SPR-based sensors utilizing carbon nanomaterials and silver-based nanocomposites were reviewed by Gupta et al [ 121 ].…”

Enhanced volatile organic compound sensing properties of BiFeO3 by carbon fibres addition

“…For better evaluation of the gas sensing performance of the prepared sensors, a comparison between the present study and similar works carried out previously [63][64][65][66][67][68][69][70] is summarized in Table 2. This comparison confirms that the BFO-based sensor exhibits comparable acetone sensing characteristics in terms of selectivity, operating temperature and response/recovery times.…”

Gas Sensors Based on Single-Wall Carbon Nanotubes

“…Physical depositions such as electron-beam evaporation [ 44 ] and sputtering [ 116 ] of the nanoparticles are the most popular methods, but chemical functionalization with nanoparticles can be achieved by hydrothermal and sol-gel methods [ 117 ]. The reported nanoparticles include metals such as Pt [ 118 , 119 ], Pd [ 120 , 121 , 122 , 123 ],Au [ 124 , 125 , 126 , 127 ], Ag [ 128 , 129 , 130 ], Cu [ 131 , 132 ], Ru [ 133 ], and metal oxides [ 56 , 134 , 135 , 136 , 137 , 138 ]. Taking Pd as an example, when H 2 gas molecules contact Pd, H 2 dissociates on the surface and forms PdH x [ 139 , 140 ], which promotes electron donation to compensate for hole carriers in the SWCNTs and leads to higher resistance.…”