Trace level toxic ammonia gas sensing of single-walled carbon nanotubes wrapped polyaniline nanofibers

Abstract

This paper presents a two-step enhancement and a comprehensive analysis of single-walled carbon nanotubes (SWCNTs) wrapped polyaniline nanofiber (NPANI) ammonia (NH3) gas sensor at room temperature. SWCNT-PANI composites are successfully synthesized using an efficient and cost-effective rapid in situ chemical polymerization method. The structural morphology and modification of the samples are characterized using field-emission scanning electron microscopy and HRTEM. FTIR and Raman spectroscopic studies are also performed to gain a better insight into the chemical environmental interaction in the as-prepared nanocomposite. The analysis confirms the successful formation of the nanocomposite. The observed NH3 gas-sensing response at 10 ppm of SWCNT, f-SWCNT (functionalised SWCNT), and SWCNT-PANI composite sensors are 5%–6%, 18%–20%, and 24%–25%, respectively. The SWCNT-PANI composite sensors have shown higher repeatability, selectivity, long-term stability, and fast response-recovery characteristics as compared to f-SWCNTs and pristine SWCNT sensors. Concentration and temperature dependent gas-sensing studies are also analyzed. The sensor response also shows a linear relationship with NH3 gas concentration and an inverse relationship with increasing temperature.

Highly Efficient Response of Ammonia Gas Sensor Based on Surfactant‐Free Sorted‐Semiconducting Single‐Walled Carbon Nanotubes at Room Temperature

“…The chemisorptions can take place by site defect on the CNTs sidewall. [22,23] As it is reported that the binding energy of chemisorbed ammonia is quite high [24] ; and their desorption from the surface of CNTs need some external excitation energy to the system. [25] The Kong et al found that adding ammonia significantly altered the electrical resistance of sc-SWCNTs.…”

Emerging MXene–Polymer Hybrid Nanocomposites for High-Performance Ammonia Sensing and Monitoring

“…Conversely, chemiresistors based on nanostructured polymers (e.g., polypyrrole (PPy), polyvinyl alcohol (PVA), polyaniline (PAN), poly (aniline co-pyrrole) (PAP), polystyrene (PS), poly 3,4-ethylene dioxythiophene (PEDOT), and cationic polyacrylamide (CPAM)) of desired functionality and conductivity continue to enhance NH 3 sensing performance [ 10 , 28 , 29 , 30 , 31 ]. Polymer-based NH 3 sensors are popular for miniaturized configuration, user, and environmentally friendly, tunable chemistries, low-cost, flexibility, and energy efficiency.…”

“…Polymer-based NH 3 sensors are popular for miniaturized configuration, user, and environmentally friendly, tunable chemistries, low-cost, flexibility, and energy efficiency. However, owing to the high affinity of polymers toward humidity and volatile organic compounds present in the environment, it exhibits poor stability and cross-sensitivity [ 10 , 28 , 29 , 30 ].…”

Recent trends in gas sensingviacarbon nanomaterials: outlook and challenges

“…The sensing mechanism is complex and different with different polymers, i.e., when a reducing gas such as NH 3 interacts with the reactive sites of the emeraldine base of PANI, protonation/ deprotonation of PANI occurs and NH 4+ ions are formed owing to the delocalization of electrons and increase in the electronegativity on its surface. 90 4. CNM hybrid nanocomposite-based gas sensors…”