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The use of metal single-atom catalysts (SACs) has recently received a lot of attention for achieving an efficient oxygen evolution reaction (OER) in water splitting because of their unique catalytic properties due to unsaturated active sites with maximum atom utilization efficacy. However, designing architectural structures with specific coordination sites to avoid metal cluster formation and stabilization of SACs on a conductive support to overcome the inhomogeneous and slow transportation of ions/molecules is quite challenging. Thus, to overcome this challenge, herein, we report the fabrication of a N-coordinated cobalt SAC (NC-Co-SAC) on a carbon matrix derived from a predesigned bimetallic Zn/Co zeolitic imidazole framework (BM-ZIF). The fabricated NC-Co-SAC was then integrated at the surface of highly conductive cellulose acetate-polyaniline (CP) electrospun nanofibers and was evaluated in terms of its OER efficacy in water splitting. Surprisingly, the designed novel NC-Co-SAC@CP electrospun nanofibers offer lowest overpotential of 320 mV at 10 mA cm−2 in 1 M KOH and a Tafel slope of 59 mV dec−1 even much better than those of the commercial IrO2 and RuO2 and most reported non-precious metal catalysts. Additionally, the designed electrode demonstrated exceptional chemical stability, thus opening up more avenues for further exploring efficient noble metal free water splitting electrocatalysts for sustainable energy conversion. [ABSTRACT FROM AUTHOR]

Two kinds of dihydropyridine derivatives, namely, 2-oxo-1,2-dihydropyridine-3-carboxylic acid (ODCA) and 2-oxo-6-phenyl-1,2-dihydropyridine-3-carboxylic acid (OPDCA) were utilized as controllers for the destruction of Al2O3 film, corrosion of Al and H2 production on Al surface in 2.0 M HCl solutions. Chemical (weight loss, open-circuit potential, gasometry) and electrochemical techniques (galvanostatic polarization, and electrochemical impedance spectroscopy) with the surface investigation of some corroded Al samples by a scanning electron microscope were used. The rate of H2 production increased with the immersion time (t) and temperature (T) and was mitigated in the presence of ODCA and OPDCA inhibitors. Galvanostatic polarization data indicated that the used compounds behaved as mixed-type inhibitors by the formation of an adsorbed film on the Al surface. The thermodynamic parameters, ΔG°ads, and Kads assured spontaneous mixed physical and chemisorption mechanisms. [ABSTRACT FROM AUTHOR]

Industrial waste consisting of dyes has emerged as a major waterbody pollutant in these modern times. Therefore, an efficient method is required to remove and address these water contaminant concerns. The current study reported the fabrication of a new hybrid type carboxylatedalginic acid (CAA) coordinated with Sn-metal (Sn-CAA) green composite absorbent for the removal of toxic dyes such as Acid Red (AR.) and Brilliant Green (BG). To obtain CAA, alginic acid was chemically oxidised via KMnO4 and it was subsequently used to coordinate with Sn2+ metal ion. The characterisation such as field emission-scanning electron microscope, X-ray powder diffraction technique and Fourier-transform-infrared spectroscopy was carried out to confirm the fabrication of CAA and Sn-CAA adsorbents. Several parameters including shaking time, pH, heating and concentration-effect were employed to conduct solid-phase extraction and UV-vis spectroscopy experiments were conducted to confirm the successful removal of toxic dyes from the aqueous media. The dye removal results established the spontaneous and endothermic nature of dye removal process as assessed through obtained thermodynamic and kinetic parameters. Furthermore, for the removal of BG and AR, the fabricated Sn-CAA-based adsorbent found to be more proficient than pristine CAA. [ABSTRACT FROM AUTHOR]

A new complex, [Ni(Tren)(Barb)(H2O)](Barb)(Barb-H)·2H2O (NiC) {Tren = tris(2-aminoethyl)amine and Barb = 5,5-diethlybarbiturate}, has been synthesized and characterized. The nickel(II) complex was grafted to g-C3N4, forming NiC@g-C3N4. The obtained NiC complex and its hybrid material NiC@g-C3N4 were characterized by FT-IR, TGA-DSC, UV–vis, SEM-EDX, and XRD. Single crystal X-ray crystallography shows that NiC exhibits NiN5O octahedral geometry. The results also show that the complex molecules are connected via N–H⋅⋅⋅⋅O hydrogen bonds. The complex NiC and NiC@g-C3N4 show oxidative stress effects on in vivo experiments. They also showed an increase in tissue damage markers that are represented by increase in tissue levels of malondialdehyde (MDA) in brain, liver, kidney and heart. Both materials showed inhibitory activity for examined antioxidants such as glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione (GSH) and glutathione reductase (GSH-R). The destructive effects were clearer for the NiC@g-C3N4 composite in liver, brain and kidney, respectively. The grafting of NiC complex in g-C3N4 is responsible for improving the catalytic activity of the compound, due to the synergistic effect of both components and facile recovery, as well recycling of the catalyst. The immobilization of the synthesized nickel(I) complex [Ni(Tren)(Barb)(H2O)](Barb)(Barb-H)•2H2O (NiC) to the graphitic carbon nitride (g-C3N4) as electron rich surface, forming the hybrid material NiC@g-C3N4, which provides both the benefits i.e improved catalytic activity owing to the synergistic effect of both components and facile recovery, recycling of the catalyst. [ABSTRACT FROM AUTHOR]

A fullerene-based photosensitizer is incorporated postsynthetically into a Zr6-based MOF, NU-1000, for enhanced singlet oxygen production. The structural organic linkers in the MOF platform also act as photosensitizers which contribute to the overall generation of singlet oxygen from the material under UV irradiation. The singlet oxygen generated by the MOF/fullerene material is shown to oxidize sulfur mustard selectively to the less toxic bis(2-chloroethyl)sulfoxide with a half-life of only 11 min. [ABSTRACT FROM AUTHOR]