Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been performed to gain insight into the structure of poly(o-phenylenediamine) (POPD). Both reported structures of ...POPD, ladder (L)- and polyaniline (P)-like, are investigated theoretically through the oligomers approach. The simulated vibrational properties of 5POPD(L) and 5POPD(P) at B3LYP/6-31G (d) along with their assignments are correlated with experimental frequencies. Vibrational spectra show characteristic peaks for both POPD(L) and POPD(P) structures and do not provide any conclusive evidence. Excited-state properties such as band gap, ionization potential, electron affinities, and HOMO–LUMO gaps of POPD(L) and POPD(P) from monomers to five repeating units are simulated. UV–vis spectra are simulated at the TD-B3LYP/6-31+G (d, p) level of theory, supportive to the ladder-like structure as the major contributor. Comparison of the calculated data with the experimental one strongly suggests that the ladder-like structure is the predominant contributor to the molecular structure of POPD; however, a small amount of POPD(P) is also believed to be present.
•Kinetic study of electrochemical degradation of PANI/DBSA/H2SO4.•Investigation of supercapacitive properties PANI/DBSA/H2SO4 in different electrolytes.•Specific capacitance of 516Fg−1 with 57% ...retention even after 1000 charge discharge cycles.•The materials showed relatively high energy and power densities of 34W hr kg−1 and 11.51Wkg−1 in 0.5M HClO4.
We report the utilization of polyaniline (PANI), co-doped with DBSA and sulfuric acid (PANI/DBSA/H2SO4), as a novel and promising electrode material for aqueous supercapacitors. The co-doped PANI/DBSA/H2SO4 salts were characterized by in situ conductance measurements, in situ UV–vis spectroelectrochemistry, cyclic voltammetry (CV) and UV–vis NIR spectroscopy. Elemental analysis of the synthesized PANI salt revealed its remarkable (50%) doping level while intrinsic viscosity indicated its highest molecular weight. Furthermore, PANI salt with best set of properties was tested for application in supercapacitors. For this purpose a systematic study was carried out in selected acidic electrolytes (HClO4, H2SO4, and H3PO4) by employing CV, Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS). Different parameters such as applied potential limits, current density as well as type and concentration of electrolytes were optimized. The kinetics of the electrochemical degradation as well as specific capacitance of the PANI film was determined in the above mentioned electrolytes, which helped in choosing the appropriate conditions and electrolyte for the maximum exploitation of this material for supercapacitor. All the results suggest 0.5M HClO4, along with other optimized parameters, as the most appropriate electrolyte solution. The PANI film showed electroactivity even after 6000 cycles applied through cyclic voltammetry. A capacitance retention of 57% after 1000 charge discharge cycles was observed in this electrolyte. Similarly, the film exhibited a specific capacitance value of 516Fg−1 with a relatively high energy density and power density of 34W h kg−1 and 11.51KWkg−1, respectively. As compared with the literature, the prepared polymer can be used as an electrode material for supercapacitors.
Energy is one the most fundamental necessities in daily life which is fulfilled from non-renewable and non-ecofriendly resources that are not only expensive in terms of costs but also depleting with ...time and causingenvironmental pollution. The quest for the renewable, eco-friendly and economic energy resources is in progression tomitigate the energy demands. In this context, cogent energy alternatives are under investigations to develop innovative strategies based on renewable, affordable and widely available resources. In these perspectives, Metal Sulfides (MS) and their derivatives are sensible, operative and eco-friendly electrocatalysts with ultramodern physiognomies because of extensive durability, porous topography, high surface area, extensive varieties, cost effectiveness, simplicity and chemical functionality. Various synthetic strategies such as hydrothermal, solvothermal and other miscellaneous techniques have been followed to design metal sulfides and their derivatives of countless compositions. The synthesized metal sulfides and their derivatives are favored for electrocatalytic solicitations with characteristic synergetic and plasmonic effects in order to explorehydrogen evolutionreaction (HER), oxygen evolution reaction (OER), overall water splitting (OWS), carbon dioxide reduction (CO2RR), and super capacitance. Appraising these synthetic strategies and electrocatalytic features, metal sulfides could be influential to attempt new, renewable and eco-friendly energy resources.
Aquatic ecosystem contaminated with toxic pollutants and heavy metals due to the rapid growth of industrialization has become a top-priority global concern exhibiting highly adverse effects on human ...health and the environment. Many treatment techniques have been envisioned for the removal of these toxic contaminants from the aqueous environment. Among these techniques, magnetic separation has attracted burgeoning research attention owing to its simplicity, eco-friendly nature, large surface area, electron mobility, and excellent performance for removing water contaminants. In particular, interfacial active nanoparticles and nanocomposites with unique structures and magnetic properties are considered as ideal provides candidates in material science for next-generation water treatment. This review gives an insight into current research activities associated with the synthesis strategies and applications of interfacially active and magnetically responsive nanomaterials and nanocomposites for sustainable purification processes. In the first half, various synthesis routes for magnetic iron oxide nanoparticles development and the corresponding formation mechanism are summarized. In the second half, we reviewed the magnetic and wettability properties of interfacially active and magnetically responsive nanocomposites and their environmental applications including oil-water separation, removal of hazardous dye-based pollutants and potentially toxic heavy metals. Finally, the review is wrapped up with major concluding remarks and future perspectives of these magnetic nanoscale composite materials for sustainable wastewater remediation.
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•Interfacially active and magnetically recoverable materials are reviewed.•An insight is given to current research associated with synthesis strategies.•Gaps beyond our notice are discussed from the future considerations' viewpoint.
Carbon nanotubes (CNTs) are known as nano-architectured allotropes of carbon, having graphene sheets that are wrapped forming a cylindrical shape. Rolling of graphene sheets in different ways makes ...CNTs either metals or narrow-band semiconductors. Over the years, researchers have devoted much attention to understanding the intriguing properties CNTs. They exhibit some unusual properties like a high degree of stiffness, a large length-to-diameter ratio, and exceptional resilience, and for this reason, they are used in a variety of applications. These properties can be manipulated by controlling the diameter, chirality, wall nature, and length of CNTs which are in turn, synthesis procedure-dependent. In this review article, various synthesis methods for the production of CNTs are thoroughly elaborated. Several characterization methods are also described in the paper. The applications of CNTs in various technologically important fields are discussed in detail. Finally, future prospects of CNTs are outlined in view of their commercial applications.
A label-free immunosensor for detection of hepatitis C (HCV) core antigen was fabricated using a ternary nanocomposite based on polypyrrole (PPy), silver doped zinc oxide (Ag-ZnO) and exfoliated ...graphene (Ex-Gr). The negatively charged anticore mAbs 19D9D6 (1 NLB monoclonal antibodies) were immobilized at the PPy/Ag-ZnO/Ex-Gr 9 % nanocomposite surface as it is suitable for non-covalent (electrostatic) immobilization for fabricating the label-free immunosensor. The isoelectric point (IEP) achieved at around pH 7 for PPy shifts to the lower value of pH 5.75 for PPy/Ag-ZnO/Ex-Gr 9 % nanocomposite. The linear sweep voltammetric (LSV) analysis of the as-prepared samples indicate high electrochemical activity. Similarly, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry confirmed the hindrance in the faradaic processes due to the presence of the interfacial biomolecules layer, after surface modification confirming the fabrication of the immunosensor. The LSV current signal response decrement for the concentration range of antigen HCV core nucleocapsid polypeptide (residues 13–40) (RNTNRRPQ DVKFPGGGQI VGGVYLLPRR) ranging from 0.001 ng mL-1 to 200 ng mL-1 was performed depicting the hindrance to electron transfer increases with increase in the antigen concentration as antigen antibody interaction takes place thickening the insulative layer of biomolecules at the interface leading to gradual decrease in the current response. The limit of detection was measured to be approximately 0.41 pg mL-1, respectively (S/N = 3). The single interfering protein doesn’t decrease the LSV current response for HCV (50 ng mL-1) depicting the immunospecificity i-e selectivity of the fabricated immunosensor. The as prepared label-free immunosensor displayed lower limit of detection, high selectivity and stability.
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•Ternary nanocomposite based on polypyrrole, silver doped zinc oxide and exfoliated graphene was prepared.•mAbs 19D9D6 (1 NLB monoclonal antibodies) were non-covalently immobilized at surface of as prepared ternary nanocomposite.•The antigen interaction takes place antibody at the surface of the biocompatible platform.•The electron transfer hindrance at the interface was depicted as decrement in the LSV current signal response.•The limit of detection was measured to be approximately 0.41 pg mL-1, respectively (S/N = 3).
Quantum mechanical calculations are performed to establish the structure of an oligomer of aniline and pyrrole Poly(Ani-co-Py), through comparison of experimental and theoretically calculated ...properties, including conductivity. The copolymer was synthesized through chemical oxidative polymerization and then confirmed from the experimental IR, UV–vis, mass spectra, elemental, XRD, TGA, and SEM analysis. Quantum mechanical calculations are performed at Density Functional Theory (DFT) and Time dependent DFT (TD-DFT) methods for the electronic and spectroscopic properties of the oligomer. A very nice correlation is found between the theory and experiment which consequences the structure of Poly(Ani-co-Py). Poly(Ani-co-Py) is not explored like other conducting polymers; however, by tuning this molecular structure, the electro-active nature of this material can be enhanced adequately.
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•Determination of chemical structure of Poly(Ani-co-Py).•Co-polymerization conducting polymer.•Determine decrease or increase in conductivity on copolymerization.•Validate the structure of Poly(Ani-co-Py) through experimental and theoretical studies.
•Polyaniline salts were synthesized by a novel and an efficacious emulsion polymerization pathway.•The salts are completely soluble in a large number and variety of organic solvents.•The salts are ...electrically highly conducting.•They provide extra ordinary resistance to the steel surfaces against harsh corrosive environment of the Oceans.
We report a sophisticated emulsion polymerization route for the synthesis of polyaniline (PANI) salts. In this process, the chemical oxidative polymerization of aniline was carried out in the presence of two dopants i.e., dodecylbenzenesulfonic acid (DBSA) and sulfuric acid (H2SO4). The synthesized PANI salts were highly soluble in a large number and variety of common organic solvents (so far highest number of solvents including the less hazardous ethanol) and showed very good conductance. Presumably the presence of DBSA and sulfuric acid moieties, respectively, contributed toward the improvement in solubility and conductance. After optimization of the reaction parameters, the obtained polymers were systematically characterized with cyclic voltammetry, in situ conductance, in situ UV–vis spectroelectrochemical and intrinsic viscosity measurements. X-ray diffraction, TGA and SEM were used for further analysis. The materials showed very good electrochemical and electrochromic reversibility and high thermal stability (up to 500°C). Moreover, potentiodynamic measurements revealed that coatings of this polymer can provide extra ordinary resistance to the steel surfaces particularly against the harsh corrosive environment of the oceans.
The synthesis of promising nanocomposite materials can always be tricky and depends a lot on the method of synthesis itself. Developing such synthesis routes, which are not only simple but also can ...effectively catch up the synergy of the compositing material, is definitely a worthy contribution towards nanomaterial science. Carbon-based materials, such as graphene oxide, and conjugative polymers, such as conductive polyaniline, are considered materials of the 21st century. This study involves a simple one pot synthesis route for obtaining a nanocomposite of polyaniline and graphene oxide with synergistic effects. The study was carried out in a systematic way by gradually changing the composition of the ingredients in the reaction bath until the formation of nanocomposite took place at some particular reaction parameters. These nanocomposites were then utilized for the fabrication of electrodes for aqueous symmetric supercapacitor devices utilizing gold or copper as current collectors. The device manifested a good capacitance value of 264 F/g at 1 A/g, magnificent rate performance, and capacitance retention of 84.09% at a high current density (10 A/g) when gold sheet electrodes were used as the current collectors. It also showed a capacitance retention of 79.83% and columbic efficiency of 99.83% after 2000 cycles.
The surface of an Au-disc electrode was modified through electro polymerization of aniline, in the presence of dodecyl benzene sulphonic acid (DBSA) and sulphuric acid (H
SO
) solution. The ...polymerization conditions were pre-optimized so that micelle formation and solution coagulation could be minimized and surfactant doped polyaniline film could be obtained through a quick, simple and one step polymerization route. The synthesized material was characterized via Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The effective surface area of the Au-disc, calculated through cyclic voltammetry, was immensely increased through a polyaniline (PANI) coating (0.04 and 0.11 cm
for bare and PANI coated gold respectively). The modified electrode was utilized for ascorbic acid (AA) sensing. The changing pH of electrolyte and scan rate influenced the PANI electrode response towards AA. The modified electrode was highly selective towards AA oxidation and showed a very low limit of detection i.e. 0.0267 μmol·L
. Moreover, the PANI coating greatly reduced the sensing potential for AA by a value of around 140 mV when compared to that on a bare gold electrode.
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