Recent advances in metal oxide/hydroxide on three-dimensional nickel foam substrate for high performance pseudocapacitive electrodes

The high demand for long-lasting and portable energy storage devices with enhanced energy and power densities has attracted researcher's interest globally. The three-dimensional (3D) nickel foam is a promising electrode material for storing energy in various devices because they possess large surface area, are very conductive and enjoy a continuous permeable 3D system. This article provides a review and detailed information on the uses of 3D nickel foam-based electrodes with metal oxides/hydroxides of different morphologies for high-performance pseudocapacitors. We assess the limitations and future prospects of 3D nickel foam-based electrodes with metal oxides/hydroxides for industrial application towards enhancing pseudocapacitors' energy storage capability.     

Synthesis,characterization, and thin‐film properties of 6‐oxoverdazyl polymers prepared by ring‐opening metathesis polymerization

Redox‐active 6‐oxoverdazyl polymers were synthesized via ring‐opening metathesis polymerization (ROMP) and their solution, bulk, and thin‐film properties investigated. Detailed studies of the ROMP method employed confirmed that stable radical polymers with controlled molecular weights and narrow molecular weight distributions (Ð < 1.2) were produced. Thermal gravimetric analysis of a representative example of the title polymers demonstrated stability up to 190 °C, while differential scanning calorimetry studies revealed a glass transition temperature of 152 °C. Comparison of the spectra of 6‐oxoverdazyl monomer 12 and polymer 13 , including FT‐IR, UV‐vis absorption, and electron paramagnetic resonance spectroscopy, was used to confirm the tolerance of the ROMP mechanism for the 6‐oxoverdazyl radical both qualitatively and quantitatively. Cyclic voltammetry studies demonstrated the ambipolar redox properties of polymer 13 (E_1/2,ox = 0.25 and E_1/2,red = ?1.35 V relative to ferrocene/ferrocenium), which were consistent with those of monomer 12 . The charge transport properties of thin films of polymer 13 were studied before and after a potential of 5 V was applied, revealing a drastic drop in the resistivity from 10⁶?10¹⁰ Ω m or more to 1.7 × 10⁴ Ω m and suggesting the potential usefulness of polymer 13 in bistable electronics. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1803–1813     

Synthesis,Biological and In Silico Studies of a Tripodal Schiff Base Derived from 2,4,6-Triamino-1,3,5-triazine and Its Trinuclear Dy(III), Er(III), and Gd(III) Salen Capped Complexes

A tripodal Schiff base ligand, 2,4,6-Tris(4-carboxybenzimino)-1,3,5-triazine (MT) and its trinuclear Dy(III), Er(III), and Gd(III) complexes were synthesized. These were characterized using UV-visible, IR, ¹H, and ¹³C NMR spectroscopies, elemental analysis, and molar conductivity measurements. The spectral studies indicate that the ligand is hexadentate and coordinates to the Ln(III) ions through the oxygen atoms of the carboxylic group. The trinuclear complexes were characterized as being bridged by carboxylate anions to the Dy(III), Er(III), and Gd(III) salen centers and displaying a coordination number of six. Biological studies revealed that MT is more active against the test micro-organisms relative to the trinuclear complexes. Acute toxicity studies revealed that MT is safe and has a wide range of effective doses (ED₅₀). In vivo antimalarial studies indicate that MT could serve as an effective antimalarial agent since it has parasitemia inhibition of 84.02% at 50 mg/kg and 65.81% at 25 mg/kg, close to the value (87.22%) of the standard drug—Artesunate. Molecular docking simulation studies on the compounds against SARS-CoV-2 (6Y84) and E. coli DNA gyrase (5MMN) revealed effective binding interactions through multiple bonding modes. The binding energy calculated for Er(III)MT-6Y84 and Er(III)MT-5MMN complexes showed active molecules with the ability to inhibit SARS-CoV-2 and E. coli DNA gyrase.     

The effect of synthesis procedure on the catalytic performance of isostructural ZIF‐8

We demonstrate the synthesis of isostructural zeolitic imidazole framework (ZIF‐8) using four distinct synthetic methods. Subsequently, the variations in physicochemical properties were analyzed through the catalytic reaction of CO₂ cycloaddition of epoxide. It was thus demonstrated that simply by changing the type of synthetic method for the preparation of ZIF‐8, the physicochemical properties were changed significantly which in turn influenced the catalytic activity of ZIF‐8. It was found that the synthetic method affected the crystal growth and consequently influenced the physicochemical properties which are crucial aspects in metal–organic framework applications. There is an almost exponential relationship between the reactivity of various ZIF‐8 samples in CO₂ cycloaddition of epoxide and the surface area, CO₂ adsorption and pore volume.     

Effects of post-thermal treatments on morphological and optical properties of NiO/Ni(OH)2 thin films synthesized by solution growth

Room temperature deposition of PVP capped nanostructured NiO/Ni(OH)₂ thin film, the morphological and optical characterizations by solution growth technique are reported. The nanostructured thin films which were deposited on optical glass substrates were annealed at different temperatures and then subjected to structural, morphological and optical characterizations. X-ray diffraction measurements of the films revealed that higher temperatures during the thermal treatment enhanced the crystallinity of the thin films. The SEM surface micrographs show non-interconnected uniformly deposited fibre-like structures with approximate lengths between 400 and 1200 nm. The optical band gap energy roughly decreased from about 2.7 eV to about 2.2 eV with thermal treatment. The absorbance of the thin films annealed at 300 and 400 °C was as high as 90% in the visible region of the electromagnetic spectrum. These materials could be useful in solar thermal conversion processes.     

Recent progress in nickel oxide-based electrodes for high-performance supercapacitors

In recent years, interest in nanostructured electrode materials for use in supercapacitors has been on the rise. Nickel oxide has been reported as a good candidate for supercapacitor applications due to its high theoretical capacitance and low cost. However, its poor electrical conductivity has resulted in actual poor specific capacitance and cycling ability. Over the years, researchers have studied various techniques to modify the structure and composition of NiO with the aim of improving its electrochemical performance. In this review, we opine that NiO-based electrodes can be fabricated using different approaches and different composite forms in order to obtain cells of high efficiency and specific capacitances. We discuss the recent advances in NiO-based electrodes fabricated using different approaches.     

Indoloquinazoline Alkaloids from Araliopsis tabouensis

Three new indoloquinazolidine‐type alkaloids, 8,13‐dihydro‐2‐methoxyindolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolin‐5(7H)‐one ( 1 ), 8,13‐dihydro‐2‐methoxy‐13‐methylindolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolin‐5(7H)‐one ( 2 ), and 5,8,13,14‐tetrahydro‐2‐methoxy‐14‐methyl‐5‐oxo‐7H‐indolo[2′,3′: 3,4]pyrido[2,1‐b]quinazolim‐6‐iun chloride ( 3 ) were isolated from Araliopsis tabouensis, together with three known compounds. The structures of the new compounds were determined primarily from 1D‐ and 2D‐NMR analysis. The antimalarial activities of compounds 1 – 5 were evaluated against Plasmodium falciparum D6 and W2 clones. The IC₅₀ values in antimalarial bioassay for compounds 2 – 5 varied from 1.8 to 4.7 μg/ml.