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An interfacial polymerization-based green approach was developed for the synthesis of polyaniline–graphene oxide (PANI-GO) nanocomposites. Instead of the commonly used organic solvents such as CHCl3, CCl4, hexane and toluene, vegetable oil was used here as the organic phase. Thus, the prepared nanocomposite was characterized by Fourier-transform infrared spectroscopy (FTIR), UV-visible spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA) techniques. The scanning electron microscopy (SEM) examinations revealed the formation of a uniform coating of PANI fibers on the surface of GO sheets. The PANI-GO composite showed pseudocapacitive behavior with a high specific capacitance of 510 F g−1 at a current density of 1 A g−1. The specific energy and specific power of the PANI-GO electrode material were calculated to be 45.3 W h kg−1 and 407.9 W kg−1, respectively, which maintained 92% stability even after completing 1000 cycles at a current density of 30 A g−1. Furthermore, the solid-state symmetric supercapacitor of the PANI-GO nanocomposite yielded an areal capacitance of 143.6 mF cm−2 at a current density of 1 mA cm−2. The symmetric supercapacitor maintains 76% of its initial areal capacitance after 4000 cycles. The PANI-GO nanocomposite was also explored for the fabrication of enzymatic glucose sensors. The amperometric response of PANI-GO indicates that the enzyme-loaded electrode material exhibited good catalytic activity towards the oxidation of glucose in the linear range of 20–80 μM. The limit of detection was found to be 12 μM with a signal-to-noise ratio of 3 (S/N = 3).

The excellent cyclic efficiency, superior reversible charge/discharge rate, and high specific power density have made supercapacitors an important class of energy storage systems in recent time. In this study, two nano-ceria-based composites were developed to use as electrode materials in supercapacitor applications. The composites were synthesized by combining ceria with conductive polyaniline (PANI) and doped with HCl and p-toluene sulfonic acid (PTSA). The materials were characterized by FTIR spectroscopy, SEM, XRD, and XPS techniques. Electrochemical studies were performed by cyclic voltammetry, galvanometric charge-discharge, and AC impedance spectroscopy. The CeO2-PANI doped with HCl and PTSA composites displayed ideal supercapacitor behavior showing higher capacitances up to 504 F g−1 and 454 F g−1, respectively, at current density of 1 A g−1 in comparison with pristine ceria (109 F g−1). Both the composites exhibited excellent specific energy (up to 100.8 W h kg−1) as well as outstanding specific power (up to 830 W kg−1). These findings support the possibility of these composites for practical applicability as electrode materials in energy storage devices.

In this study, we report an enormously simple green approach for the synthesis of polyaniline hybrid (PANI-SO) nanofibers in emeraldine salt form. We have carried out the synthesis via an interfacial polymerization method using vegetable oil as an organic phase instead of the commonly used solvents like CHCl3, CCl4, etc. Characterization techniques such as Fourier transform infrared (FTIR), UV–visible, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) have been used for studying the synthesized polyaniline hybrid nanofibers. An interesting observation is the crystallization of small organic molecules in the PANI matrix. PANI-SO shows a pseudocapacitance behavior with a capacitance value of 302 F g–1 at a current density of 1 A g–1. In addition, the material shows an energy density of 26.8 W h kg–1 and a maximum power density of 402.6 W kg–1. Furthermore, the PANI-SO electrode maintains about 84% of the initial capacitance after 1000 cycles. Similarly, the PANI-SO symmetric solid-state supercapacitor shows an areal capacitance of 118.7 mF cm–2 and retains a stability of 80% even after 1000 cycles. Thus, the PANI-SO electrode shows a good cyclic performance, which implies the structural stability of PANI-SO nanofibers. The electrochemical properties of PANI-SO are compared with those of PANI nanofibers synthesized by taking CHCl3 as the organic phase and keeping all other parameters identical. PANI-SO is observed to be a superior material compared to the latter one. All electrochemical analyses show that the PANI synthesized using cooking soyabean oil (PANI-SO) is an effective supercapacitor material.

Two new aliphatic oximes featuring additional pyridyl functionality are reported as highly selective colorimetric receptors for fluoride ion recognition. H-bonding mediated binding of fluoride ion to both the receptors are reasonably labile and the fluoride free receptor species are automatically regenerated after a short interval. This allows reuse of both the receptors for colorimetric fluoride recognition upto three cycles without any need for reactivation.

The possibilities to employ phenol and oxime functionalities as the fluoride recognition motif are investigated. In this regard, two new phenolic oximes H1 and H2 were prepared where the two units are linked via different aliphatic spacers. Among them, H1 exhibits intense and instantaneous colour change upon addition of fluoride ion which is clearly discernible by the “naked eye”. Optical, 1H NMR and CV analysis established that H1 is a highly selective receptor for fluoride ion as compared to other anions tested during this investigation.