Graphene/Nickel Oxide-Based Nanocomposite of Polyaniline with Special Reference to Ammonia Sensing

Abstract

Polyaniline@graphene/nickel oxide (Pani@GN/NiO), polyaniline/graphene (Pani/GN), and polyaniline/nickel oxide (Pani/NiO) nanocomposites and polyaniline (Pani) were successfully synthesized and tested for ammonia sensing. Pani@GN/NiO, Pani/NiO, Pani/GN, and Pani were characterized using X-ray diffraction, UV–vis spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The as-prepared materials were studied for comparative dc electrical conductivity and the change in their electrical conductivity on exposure to ammonia vapors followed by ambient air at room temperature. It was observed that the incorporation of GN/NiO in Pani showed about 99 times greater amplitude of conductivity change than pure Pani on exposure to ammonia vapors followed by ambient air. The fast response and excellent recovery time could probably be ascribed to the relatively high surface area of the Pani@GN/NiO nanocomposite, proper sensing channels, and efficaciously available active sites. Pani@GN/NiO was observed to show better selectivity toward ammonia because of the comparatively high basic nature of ammonia than other volatile organic compounds tested. The sensing mechanism was explained on the basis of the simple acid–base chemistry of Pani.

Electrical Conductivity Based Ammonia Sensing Properties of Polypyrrole/MoS2 Nanocomposite

“…The main reason for a decrease and increase in electrical conductivity is due to chemisorptions and desorption of ammonia respectively, involving the interaction between the lone pair of ammonia and positive polarons on the polypyrrole backbone. The results show that there is no chemical reaction between ammonia and polypyrrole leading to complete reversibility of electrical conductivity due to un-doping of the polymer [ 12 , 30 ].…”

“…Husain et al fabricated a pellet-shaped ammonia sensor utilizing polythiophene/ multi walled carbon nanotubes and polythiophene/ single walled carbon nanotubes (PTh/MWCNT and PTh/SWCNT) nanocomposites which can detect it selectively at an extremely low concentration of 0.1 and 0.5 ppm, respectively [ 16 , 17 ]. Ahmad et al reported a novel pellet-shaped ammonia sensor based on Pani/nickel oxide/graphene nanocomposites with lower detection limit of 170 ppm at room temperature [ 30 ].…”

Ultrasensitive polyaniline‐nickel oxide cladding modified with urease immobilized intrinsic optical fiber urea biosensor

“…However, in present case no any characteristics peaks shown in above mentioned range but a broad bump observed which reveals the amorphous nature of PANI. In PANI-NiO composite the characteristics peaks appears at 2θ = 37 , 43 , 62 , and 75 , respectively, corresponding to (111), (200), (220), and (310) indices confirmed the dispersion of NiO nanoparticles in the PANI matrix 33.…”

Synthesis, Characterization and Electrochemical Performance of a Redox-Responsive Polybenzopyrrole@Nickel Oxide Nanocomposite for Robust and Efficient Faraday Energy Storage

“…On the other hand, the sharp peaks at 2θ = 37.3° (111), 43.4° (200), 62.6° (220), 74.9° (311), and 78.7° (222) revealed the presence of face-centered core crystalline NiO (JCPDS no. 04-0835) embedded in Pbp [ 44 , 45 , 46 ]. The appearance of characteristic diffraction peaks in the Pbp@NiO 0.2 suggests that NiO is embedded in the Pbp host matrix and yet maintains a high degree of crystallinity.…”