1,721,076 research outputs found
Electroreduction of Iron and Free-Base Nitrocorroles in Non-Aqueous Media
No full textThe electrochemistry and spectroscopic properties of
iron corroles having an NO axial ligand and NO2 at one or
two β-pyrrole positions of the macrocycle were
investigated in benzonitrile, pyridine and dichloromethane
containing 0.1 M tetra-n-butylammonium perchlorate
(TBAP) as supporting electrolyte. In addition to the β-
pyrrole NO2 groups, the compounds also contain NO2,
CH3 or OCH3 substituents at the three meso-phenyl rings
of the macrocycle. Structures of the investigated iron
corroles are shown in Chart 1. Each iron(III) corrole
exhibits one oxidation and up to five reductions,
depending on the solvent, number and position of nitro
groups and specific substituents (R groups) on the corrole
macrocycle. The first reduction is reversible and involves
an Fe3+/Fe2+ process which occurs in the range of E1/2
values between -0.35 and +0.31 V vs SCE. Further
reductions at the iron center, at the NO axial ligand, or at
the π ring system of the corrole macrocycle occur at more
negative potentials. Several oxidations are also observed
at potentials between +0.82 and +1.37 V vs SCE. Thinlayer
UV-visible and IR spectroelectrochemistry, along
with ESR spectroscopy were used to study the site of
electron transfer.
Several free-base nitrocorroles with similar
macrocycles were also investigated as to their redox
properties and comparisons are made between this series
of compounds and previously investigated free-base
corroles having electron donating or electron withdrawing
substituents at the three meso positions of the phenyl
rings in triphenyl substituted corroles.1
Comparisons are
also made between the metallated corroles in Chart 1 and
metallocorroles containing copper, 2 germanium,2 silver3
or other central metal ions
Green synthesis and characterization of titanium dioxide nanoparticles and their photocatalytic activity
No full textStructural and Energetic Insights into SEI Precursors and Their Interactions in Lithium-Ion Batteries
No full textSurface and in-depth chemistry of sulfuric and perchloric acid intercalated graphite explored through secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM)
No full textGraphite can be considered one of the most studied materials for technological application in batteries, energy, electronics, catalysis, and water purification. The intercalation of ions and molecules is often the fundamental mechanism behind these technological applications.
Thirty years after the publication of the model, there are still several unclear mechanisms related to the intercalation of solvated anions into graphite that deserve to be more deeply investigated.
In this article, we describe how ToF-SIMS can be combined with in situ and ex-situ AFM to correlate changes in the topographical features with changes in the surface and in-depth chemistry of GIC samples obtained from HOPG electrochemically intercalated in sulfuric and perchloric acid aqueous solution. Thanks to this combined approach, the interpretative model of intercalation mechanism was revised demonstrating that graphite structural defects are areas of preferential access for the solvated electrolytes. EGO formation, gas evolution, and blister growth can take place at the subsurface as well as in the bulk of the electrode by penetration through rifts or diffused step edges. Finally, the reduction of the intercalated carbon lattice is not usually accompanied by complete ejection of the intercalated electrolyte anions
Influence of surface roughening of Titanium substrate in the electrochemical activity of Manganese oxide thin film electrode in anodic oxidation of dye-containing solutions
No full textPrevious work has verified the possibility to obtain mechanically, chemically and electrically stable electrodes based on manganese oxide (MnOx) thin films for anodic oxidation of solutions containing the RV5 azodye. To improve the morphological and electrochemical properties of these materials, in this study, a surface modification of the titanium support has been presented. Chemically modified surfaces were obtained by etching titanium substrates in hydrocloridric acid at high temperature. Untreated and modified electrodes were coated sequentially with a RuOx film, as interlayer and a MnOx film obtained by adopting three different techniques including anodic electrodeposition, cathodic electrodeposition and thermal decomposition. Surface morphology, topography and composition of all the electrodes were investigated by profilometric and TOF-SIMS analysis. Anodes electrochemical activities were first determined by cyclic voltammetry, and then in the treatment of solutions containing the azo dye Reactive Violet 5 (RV5), as model pollutant, in undivided cell under galvanostatic conditions. The results show that the surface microstructure modifies substantially the electrochemical response of selected electrodes
Advances in Structural and Morphological Characterization of Thin Magnetic Films: A Review
No full text: The present review places emphasis on a comprehensive survey of experimental techniques to probe the structural and morphological features at the nanoscale range in thin magnetic films, incorporating those available at in-house laboratories as well as those at state-of-the-art synchrotron radiation facilities. This elucidating the range of available techniques, and the information they can yield represents a step for advancing the understanding of and for unlocking new possibilities in the design and optimization of thin magnetic films across a wide range of applications
ToF-SIMS investigation of gilt and painted leather: identification of indigo, oil binder and gold varnish
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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