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![A, A plausible mechanism for hydrogen evolution reaction on polyaniline (PANI)-coated copper. B, Protonated emeraldine and deprotonated emeraldine 46 [Colour figure can be viewed at wileyonlinelibrary.com]](profile/Harinipriya-Seshadri/publication/321167294/figure/fig5/AS:566664685158400@1512114797131/A-A-plausible-mechanism-for-hydrogen-evolution-reaction-on-polyaniline-PANI-coated.png)
A, A plausible mechanism for hydrogen evolution reaction on polyaniline (PANI)-coated copper. B, Protonated emeraldine and deprotonated emeraldine 46 [Colour figure can be viewed at wileyonlinelibrary.com]
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Emeraldine salt of polyaniline-coated copper substrate was used as a cathode to study hydrogen evolution reaction in 1M H2SO4. Hydrogen evolution reaction in acidic medium followed Grotthus mechanism, where proton hops randomly on the surface of polyaniline. With Randles-Sevcik equation, the average value of diffusion coefficient for H⁺ on polyanil...
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... sharp cathodic peak indicated efficient proton adsorption on the PANI surface. The anodic peak was very weak because adsorbed protons were not released back to the electrolyte completely as depicted in the mechanism ( Figure 6A). At 200 mV s −1 , the peak current was identical to that of copper, 32 which indicated that at 200-mV s −1 PANI corroded from the metal surface and the uncoated copper reacts with the electrolyte. ...
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... high value of R s provided evidence for the fact that the hydronium ion transport from bulk to electrode/electrolyte interface acts as the rate determination step for HER on the ES-coated copper sur- face. These results supported the predicted Grotthus mech- anism ( Figure 6A), where proton exchange happened between the bulk of the electrolyte and the electrical double layer as demonstrated by NMR analysis in the following section. ...
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... plausible mechanism of proton diffusion on the PANI surface resembled the Heyrovsky mechanism. In the current studies, the proton diffusion was via the Grotthus mechanism; the steps involved in the mecha- nism ( Figure 6A) were as follows: PANI-coated copper reacted with hydronium ion, leading to quaternary ammonium cation and water, proton hopped randomly on the surface of PANI and was the intermediate species for HER, protons reduced to form H 2 gas, and further pro- tonation of PANI occurred. H 3 O + from bulk protonated PANI through a supply of hydronium ion. ...
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... stabiliza- tion of protonated quaternary ammonium cation via pro- ton hopping and further supply of protons via exchange from the bulk electrolyte provided PANI the ability to store hydrogen in the form of proton in its conjugation. Figure 6B showed a protonated chain of PANI. 46 The pro- ton-rich region of the structure enabled it to exchange protons from a solid state to its medium, which was confirmed by NMR, UV-Vis, CV, and LSV studies. ...
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... constant value of D indicated exchange of protons from its solid state to bulk electrolyte after 40 mV s −1 . Thus, Figure 7A supports the mechanism proposed in Figure 6A, as well as the ability of proton storage on the PANI surface at lower pH and faster scan rates as demonstrated by CV, LSV, UV-Vis, and NMR studies (Section 6). ...
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Citations
... On the other hand, the PANI/NF spectrum displayed additional peaks between 10° to 40°, signifying the successful deposition of PANI over the NF. This was further corroborated by distinct peaks that align with literature findings [9]. AC's XRD pattern in Figure 2a exhibited broad peaks, indicative of its predominantly amorphous structure with a hint of crystallinity [6]. ...
... On the other hand, the PANI/NF spectrum displayed additional peaks between 10 • to 40 • , signifying the successful deposition of PANI over the NF. This was further corroborated by distinct peaks that align with literature findings [9]. AC's XRD pattern in Figure 2a exhibited broad peaks, indicative of its predominantly amorphous structure with a hint of crystallinity [6]. ...
This research delves into asymmetric supercapacitor (ASC) design, utilizing activated carbon from bamboo poles (AC) and electrodeposited polyaniline (PANI) on nickel foam (NF) as key active components. The composite electrode formed from AC and PANI exhibited enhanced electrochemical attributes in various electrochemical configurations. The specified ASC, PANI@AC/NF//AC/NF, demonstrated a potential of 1.8 V. Impressively, it reached an areal capacitance measuring 423 mF/cm2, coupled with an energy density of 190 µWh/cm2 at a power density of 900 µW/cm2, and maintained ~82% capacitance after 5000 GCD cycles. Notably, our developed ASC presents outstanding research potential for scholars and scientists.
... Moreover, electrochemical impedance spectroscopy (EIS) with applied across the frequencies ranging from 0.1 Hz to 100 kHz, and the retention test of the constructed SC was performed at high current density (2 Ag -1 ) over 2000 cycles. [20]. On the other hand, the phase and the interlayer gap of RGO were investigated and confirm high intensity peak at 24.10 for plane (002) and at 42.60 for (011) facets [21]. ...
... As depicted in the table, the resistances associated with RGO exhibited reasonable values, whereas RGO.Ag demonstrated the lowest resistance, attributed to the inclusion of highly conductive silver resulting in a significant reduction in resistivity. Conversely, the introduction of PANI to the composite contributed to an increase in resistance, primarily due to the comparatively lower conductivity of PANI when compared to both silver and reduced graphene oxide [19][20][21]. ...
... The sharpness and intensity of the peak show the degree of orientation and population of crystallites in that plane. [28] The sharp and intense peak at 24.8°i ndicates the extended π conjugation by benzenoid and quinoid groups in the polyaniline chain, [19d,29] indicating that the benzenoid and quinoid groups are orderly arranged. The lower and higher ratios of SDS make the polymer amorphous, whereas the 0.5 SDS-PANI enhances the partial crystallinity of polyaniline with improved morphology and other properties. ...
The fluorescence quenching studies using conducting polymers (CPs) have greatly contributed in the trace detection of high energy materials (HEMs) with nitro functional groups. Polyaniline doped with the anion surfactant sodium dodecyl sulfate (SDS) acts as a fluorophore and is used in fluorescence quenching studies to detect HEMs at trace levels. A mechanistic approach to understanding electron transfer during the interaction of fluorophore with HEMs were studied by using spectroscopic and electrochemical techniques. The presence of conjugation in conducting polymer shows a molecular wire effect during fluorescence quenching by trace level of HEMs by quenching several emissions in polymer chains. The Stern‐Volmer(S‐V) and limit of detection(LOD) plots give quenching mechanism and the efficiency of quenching. These values indicate that TNT had good sensitivity compared to other HEMs such as RDX, PETN, CL‐20 and CRCC. The FTIR and Raman studies were used to understand the interaction between nitro groups of HEMs with the benzenoid, polaronic and semi‐quinoid units of doped polyaniline. The cyclic voltammetry studies revealed shift in potential and current during the interaction of the fluorophore with HEMs, and these results were combined with fluorescence studies for better understanding of the possible mechanism of quenching.
... 31 Scherrer's relation was utilized to calculate the size of NiO nanosheets associated with the (200) peak, resulting in an estimated size of 30 nm. 32 The XRD pattern of PANI shows broad peaks at 20.2 and 25.2°, indicating its amorphous nature and corresponding to the lattice planes (113) and (322). 33 For the PNG nanocomposite, a sharp peak at 26.6°is observed, representing the (002) plane attributed to graphene. 34 Notably, the incorporation of NiO nanosheets within the PNG network prevents the restacking of graphene sheets, thereby improving the conductivity of the PNG electrode material. ...
In this study, a PANI/NiO/Graphene (PNG) nanocomposite was synthesized using a cost-effective wet chemical polymerization method. This nanocomposite was used to fabricate supercapacitor electrodes in a nontoxic, noncorrosive, and neutral hybrid gel polymer (PVA/Na2SO4) electrolyte. The electrodes made from the PNG material underwent analysis using electrochemical techniques, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy in a three-electrode system. For a deeper exploration of the supercapacitive properties of the PNG material, galvanostatic charge–discharge was employed. A practical two-electrode symmetric device powered by the hybrid PVA/Na2SO4 electrolyte was fabricated to calculate specific capacitance, energy density, and power density. The designed PNG material demonstrates excellent electrochemical behavior, exhibiting an improved energy density of 59.41 W h/kg at 850 W/kg. Furthermore, the PNG electrode shows excellent reversibility along with enhanced energy density and retains 89% of its capacitance after 2000 cycles. These outstanding properties of the PNG material can be attributed to the synergistic effect of PANI nanofibrous, NiO, and graphene two-dimensional structures.
... However, hydrogen is identified as a climate-friendly fuel that can power industries, buildings, ships, and planes without emitting carbon dioxide, making it an essential part of the transition to a low-carbon global economy and meeting net-zero greenhouse gas emission targets [6]. However, attention must be paid to avoiding hydrogen leakage, as this is critical to maximizing the fuel's climatic benefits, regardless of how it is created [7]. While ...
Porous TiO2-doped polyaniline and polyaniline nanocomposite fibers prepared by the in situ polymerization technique using anionic surfactant in an ice bath were studied. The prepared nanocomposites were characterized by FTIR spectroscopy and XRD patterns for structural analysis. The surface morphology of the polyaniline and its nanocomposites was examined using SEM images. DC conductivity shows the three levels of conductivity inherent in a semiconductor. Among the nanocomposites, the maximum DC conductivity is 5.6 S/cm for 3 wt.% polyaniline-TiO2 nanocomposite. Cyclic voltammetry shows the properties of PANI due to the redox peaks of 0.93 V and 0.24 V. Both peaks are due to the redox transition of PANI from the semiconductor to the conductive state. The hydrogen absorption capacity is approximately 4.5 wt.%, but at 60 °C the capacity doubles to approximately 7.3 wt.%. Conversely, 3 wt.% PANI—TiO2 nanocomposites have a high absorption capacity of 10.4 wt.% compared to other nanocomposites. An overall desorption capacity of 10.4 wt.% reduced to 96% was found for 3 wt.% TiO2-doped PANI nanocomposites.
... ∘ , and 2 = 25.68 ∘ , these peaks in the diffraction pattern correspond to 121, 113, and 322 crystal planes [19,20]. The crystal planes indicate the growth directions of chains, and the intensity (peak height) is referred to the population of crystallites in that plane [21]. The average crystallite size ( ) is calculated by using the Scherrer formula [( = / cos ), where = 0.9 is the shape factor, and is the full width at half maxima of the crystalline peak in radians] to the maximum peak ( = 3.2 nm) [22]. ...
One-dimensional nanostructures of PANI: PVA-g-EI nanocomposite are prepared by the interfacial polymerization method. The properties of a resulting green powder are studied by the X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and infrared spectroscopy (FTIR). Prepared thin films were characterized by UV-Vis and photoluminescence (PL) spectroscopies. The XRD pattern of the nanocomposite shows that the higher volume fraction of crystalline phases corresponds to the PANI polymer with the accepted monoclinic unit cell of PVA. Nano-sized irregular particles arranged in clusters appear in the TEM measurements and SEM images, which testifies to the agglomeration without uniform packing. EDX confirms that the PVA-g-EI is incorporated in the structure of the polymer nanocomposite. A significant shift in the absorption edge with three PL independent emission peaks again confirms that PANI/PVA-g-EI form a nanocomposite.
... , (311), (222), (400), (511), and (440) of spinel CuFe 2 O 4 . The nanohybrids 1-PANI/ CuFe 2 O 4 , 3-PANI/CuFe 2 O 4 , and 5-PANI/CuFe 2 O 4 showed some new peaks at 2θ = 14.23°, 20.62°, and 25.12° associated with PANI associated with (121), (113), and (322) PANI planes(Padmapriyal et al. 2017;Riaz and Zia 2020). The average crystallite size "D" is determined from average full-width half maxima (FWHM) of all reflection peaks using Scherrer formula: D = kλ/β Cos θ, where β is FWHM, λ is wave length of Cu-Kα source (0.15406 nm), and θ is diffraction angle. ...
Tetracycline hydrochloride (TC-HCl) is widely implemented as a wide-ranging antibacterial drug in medical care and animal husbandry, in spite of having negative effects on the environment and human health. Photocatalytic treatment is one of the popular techniques used to treat TC-HCl in wastewater. In this study, we have used CuFe2O4 and CuFe2O4/polyaniline (PANI) nanohybrids as photocatalysts for the degradation of TC-HCl. The metal ferrite and its nanohybrids were synthesized by co-precipitation method. FTIR, UV-Vis, XRD, and SEM-EDX were used to characterize the synthesized nanohybrids. The optical band gaps were estimated to be 2.74 eV for CuFe2O4, 1.72 eV for 1-PANI/CuFe2O4, 1.66 eV for 3-PANI/CuFe2O4, and 1.31 eV for 5-PANI/CuFe2O4. The photocatalytic performance of the nanohybrids appeared superior than pristine CuFe2O4, and maximum photocatalytic degradation was observed to be 86% within 120 min using 5-PANI/CuFe2O4 as the photocatalyst. The degraded fragments were analyzed by LCMS technique, and a tentative mechanism for the degradation of TC-HCl was proposed.
... Le polymère est de nature semi-cristalline, car l'unité présente des pics nets, dus à la présence de groupes benzénoïdes et quinonoïdes dans la polyaniline [268]. La grande largeur (2θ) de la majorité de ces pics représentait le degré d'orientation des chaînes de polymère en raison des longues chaînes de PANI et d'une structure plus ordonnée et a également montré un bon accord avec ceux de la littérature [269]. [270]. ...
La présence de composés pharmaceutiques dans l'eau, en particulier d'antibiotiques, est un problème important qui peut avoir un impact négatif sur la vie aquatique et la santé publique. Les méthodes classiques d'élimination de ces composés ne sont pas toujours efficaces et peuvent générer des sous-produits nocifs. Il est donc urgent de développer des méthodes durables et efficaces pour éliminer les composés pharmaceutiques de l'eau. Bien que la photocatalyse soit une technique prometteuse pour l'élimination de ces composés, des recherches supplémentaires sont nécessaires pour optimiser son efficacité et son efficience. Afin de contribuer à la résolution de ce problème, cette thèse s'est concentrée sur le développement de solutions photocatalytiques durables pour l'élimination des composés pharmaceutiques de l'eau. Un groupe d'antibiotiques provenant d'une usine pharmaceutique a été traité par un processus propre, la photocatalyse, en utilisant des cristaux de sillénite comme photocatalyseurs récents. Ces photocatalyseurs de sillénite ont été synthétisés par la méthode sol-gel et ont été caractérisés avant d'être utilisés. L’application de photocatalyse a été modélisé et optimisé à l'aide d'une méthode de réseau neuronal artificiel, puis comparé en présence de différents catalyseurs. Les résultats montrent que la sillénite Bi12TiO20 est le meilleur candidat pour les applications photocatalytiques, avec une efficacité de 94% pour une solution de Céfixime avec une concentration initiale de 10 mg/L en seulement 3 heures dans des conditions optimales. De plus, la qualité de cette méthode a été vérifiée par différentes techniques en montrant que le polluant a été minéralisé avec succès avec la présence d'une petite quantité de petits sous-produits. Ensuite, un système de traitement photocatalytique a été proposé comme solution à grande échelle pour le processus précédent et une évaluation économique intégrée de ce système a été réalisée afin d'examiner son applicabilité à grande échelle. L'efficacité de ce processus a également été améliorée en le combinant avec une autre technique de traitement, à savoir l'adsorption à l'aide d'un polymère intéressant, la polyaniline. Les résultats montrent que ce système hybride peut éliminer une concentration très élevée de Céfixime de 30 mg/L, presque à 100%, en seulement 2 heures, ce qui est mieux que les recherches précédentes. Le domaine de l'ingénierie a également été appliqué dans cette thèse en concevant un réacteur à agitation continue et en utilisant un système hybride composé de graphite comme adsorbant et de ZnO comme catalyseur. Les résultats montrent que ce type de réacteur peut être une méthode prometteuse pour éliminer les antibiotiques des eaux usées dans des applications à grande échelle.
... The polymer is semi-crystalline in nature because the unit shows sharp peaks due to the presence of benzenoid and quinonoid groups in the polyaniline [281]. The large width (2θ) of the majority of these peaks represented the degree of orientation of the polymer chains due to long PANI chains and a more ordered structure and also showed good agreement with those in the literature [282]. correspond to quinone and benzene ring-stretching deformations, respectively [283]. ...
The presence of pharmaceutical compounds in water, especially antibiotics, is a significant concern that can negatively impact both aquatic life and public health. Classique removal methods for these compounds are not always effective and can generate harmful by-products. Consequently, there is a pressing need to develop sustainable and efficient methods for the removal of pharmaceutical compounds from water. Although photocatalysis shows potential as a technique for removing these compounds, further research is necessary to optimize its effectiveness and efficiency. In order to contribute to addressing this issue, this thesis focused on developing sustainable photocatalytic solutions for eliminating pharmaceutical compounds from water. A group of antibiotics taken from a pharmaceutical factory have been treated through a clean process which is photocatalysis using sillenite crystals as recent photocatalysts. These sillenite photocatalysts have been synthesized by sol-gel method catalysts and they have been characterized before they were used. The photocatalysis system has been modeled and optimized using an artificial neural network method and then compared in the presence of different catalysts. The results show that sillenite Bi12TiO20 is the best candidate in photocatalytic applications, with an efficiency of 94% for a Cefixime solution with an initial concentration of 10 mg/L in only 3 h under optimal conditions. Furthermore, the quality of this process has been verified by various techniques by showing that the pollutant has been mineralized successfully with the presence of a little amount of small by-products. After that, a photocatalytic treatment system has been proposed as a large-scale for the previous process and an integrated economic assessment for this system has been performed to examine its applicability in large-scale applications. The efficiency of this process has also been improved by combining it with another treatment technique, which is adsorption using the interesting polymer polyaniline. The results show that this hybrid system can remove a very high Cefixime concentration of 30 mg/L, almost 100%, within only 2 hours and this is better than previous investigations. The engineering field has also been applied in this thesis by designing a continuous stirring tank reactor (CSTR) and using a hybrid system made of graphite as an adsorbent and ZnO as a catalyst. The results show that this type of reactor can be a promising method for removing antibiotics from wastewater in large-scale applications.
... The peak centered at 2θ = 22.70° may be ascribed to a periodicity parallel to the polymer chain [44] and represents the characteristic distance between the ring planes of benzene rings in adjacent chains or the close-contact inter-chain distance [45]. The peak at 2θ = 25.59° may be caused by the periodicity perpendicular to the polymer chain [46,47]. These values indicate that the majority of PANI chains are oriented in these three crystal planes [48]. ...
The copolymer poly (aniline-co-orthotoluidine) noted poly (ANI-co-OT) was chemically synthesized and characterized by FT-IR, UV–Vis, and XRD techniques. XRD results confirm the amorphous nature of the copolymer. FT-IR and UV–Vis results indicate that the spectrum of the copolymer includes all the bands relating to the functional groups of the homopolymers polyaniline (PANI) and poly-orthotoluidine (POT). It was revealed that, contrastingly to the copolymer’s solubility in dimethylformamide (DMF), the homopolymers have a low solubility. The potentiodynamic polarization technique has been employed in order to study this copolymer’s inhibition effects on the corrosion of carbon steel X52 in a 3.5% NaCl solution. The aforementioned study illuminated the following. The copolymer exhibits high inhibition activity towards the corrosive action of NaCl and its adsorption obeys the Langmuir adsorption isotherm model. The calculated Gibbs free energy (∆G⁰ads) revealed the chemisorption of this copolymer on the surface of the carbon steel. In addition, a synergistic effect was observed when the copolymer poly (ANI-co-OT) was mixed with the amphoteric surfactant cocamidopropyl betaine (CAPB) where the inhibition efficiency increased from 68 to 92%. Also, it was perceived that the adsorption of the copolymer/surfactant mixture adhered to the Langmuir adsorption isotherm. The calculated Gibbs free energy (∆G⁰ads) revealed both chemisorption and physisorption of the mixed copolymer and surfactant on the carbon steel surface. Increasing temperature slightly decreases the inhibition efficiency, indicating that the mixed copolymer and surfactant adsorb on the carbon steel surface via simultaneous chemisorption and physisorption. The good inhibition efficiency was related to the formation of inhibitor–adsorption film on the surface of the carbon steel, which is confirmed by the surface analysis. Quantum chemical results using the density functional theory (DFT) corroborated the experimental results.
