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Disproportionation

About: Disproportionation is a research topic. Over the lifetime, 6423 publications have been published within this topic receiving 125210 citations. The topic is also known as: dismutation & redox disproportionation.


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Journal ArticleDOI
TL;DR: In situ spectroelectrochemical techniques are demonstrated to demonstrate that the stabilization of surface-associated intermediate Mn(3+) species relative to charge disproportionation is an effective strategy to lower the overpotential for water oxidation by MnO(2).
Abstract: The development of Mn-oxide electrocatalysts for the oxidation of H(2)O to O(2) has been the subject of intensive researches not only for their importance as components of artificial photosynthetic systems, but also as O(2)-evolving centers in photosystem II. However, limited knowledge of the mechanisms underlying this oxidation reaction hampers the ability to rationally design effective catalysts. Herein, using in situ spectroelectrochemical techniques, we demonstrate that the stabilization of surface-associated intermediate Mn(3+) species relative to charge disproportionation is an effective strategy to lower the overpotential for water oxidation by MnO(2). The formation of N-Mn bonds via the coordination of amine groups of poly(allylamine hydrochloride) to the surface Mn sites of MnO(2) electrodes effectively stabilized the Mn(3+) species, resulting in an ~500-mV negative shift of the onset potential for the O(2) evolution reaction at neutral pH.

299 citations

Journal ArticleDOI
TL;DR: A series of oxoperoxovanadium(V) complexes were characterized as functional models for the vanadium haloperoxidase enzymes as mentioned in this paper, and the crystal structures of these complexes were obtained.
Abstract: A series of oxoperoxovanadium(V) complexes (ligands: H3nta = nitrilotriacetic acid, H3heida = N-(2-hydroxyethyl)iminodiacetic acid, H2ada = N-(2-amidomethyl)iminodiacetic acid, Hbpg = N,N-bis(2-pyridylmethyl)glycine, and tpa = N,N,N-tris(2-pyridylmethyl)amine) were characterized as functional models for the vanadium haloperoxidase enzymes. The crystal structures of K[VO(O2)Hheida], K[VO(O2)ada], [VO(O2)bpg], and H[VO(O2)bpg]2(ClO4) were obtained. These complexes all possess a distorted pentagonal bipyramidal coordination sphere containing a side-on bound peroxide. In the presence of sufficient acid equivalents these complexes catalyze the two-electron oxidation of bromide or iodide by peroxide. Halogenation of an organic substrate was demonstrated by following the visible conversion of Phenol Red to Bromophenol Blue. In the absence of substrate, dioxygen can be generated by the halide-assisted disproportionation of hydrogen peroxide. In addition, some of these complexes can efficiently catalyze the perox...

296 citations

Journal ArticleDOI
TL;DR: A review of the reactions of NO coordinated to transition metals, and of interest in air pollution control, organo-nitorgen compound synthesis (from nitric oxide, by using transition metal catalysts), and theoretical studies of differences between CO and NO binding to metals, examines the three principal bonding modes in nitrosyl complexes.
Abstract: A review of the reactions of nitric oxide coordinated to transition metals, and of interest in air pollution control, organo-nitorgen compound synthesis (from nitric oxide, by using transition metal catalysts), and theoretical studies of differences between CO and NO binding to metals, examines the three principal bonding modes in nitrosyl complexes (all metal-to-nitrogen interactions) which involve terminal linear M-N-O groups, terminal bent M-N-O groups (the applicability of the 18-electron rule), and bridging NO groups and covers nucleophilic attack (the nitroprusside ion, reactions of other nitrosyl complexes with nucleophiles); electrophilic attack (the protonation of NO, oxygenation, other O-atom transfer reactions, and formation of N-C bonds); reduction (one-electron and multi-electron processes, and heterogeneous reduction of NO); homogeneous disproportionation of NO (reaction of coordinated NO with nitric oxide, reactions of NO with CO catalyzed by metal complexes); and other reactions, including NO insertion reactions.

288 citations

Journal ArticleDOI
TL;DR: In this paper, a single-metal redox flow battery employing chromium(III) acetylacetonate in tetraethylammonium tetrafluoroborate and acetonitrile has been investigated using electrochemical techniques.

287 citations

Journal ArticleDOI
TL;DR: In this article, the Ni/La2O3 catalyst was used for carbon dioxide reforming of methane to synthesis gas, and it was found that the Ni surface is blocked by lanthanum species.
Abstract: Carbon dioxide reforming of methane to synthesis gas was studied employing Ni/La2O3 catalysts. It was found that, in contrast to the performance of other nickel-based catalysts (e.g. Ni/Al2O3 and Ni/CaO) which exhibit continuous deactivation with time on stream, the rate over the Ni/La2O3 catalyst increases during the initial 2–5 h of reaction and then tends to be essentially invariable with time on stream, displaying very good stability. X-ray diffraction (XRD) studies reveal that a large CO2 pool, stored in the form of La2O2CO3, is accumulating on the Ni/La2O3 catalyst, following exposure to the CH4/CO2 mixture at reaction conditions. Results of H2- and CO-temperature-programmed desorption reveal that the HNi bond is weakened and CO disproportionation is unfavoured on the Ni/La2O3 catalyst, as compared to the Ni/Al2O3 catalyst. Comparison of H2 and CO uptake and Ni dispersion by XRD shows that H2 and CO uptakes are significantly suppressed, by ca. 3–10 times, suggesting that a large portion of the Ni surface is blocked by lanthanum species. It is proposed that the interaction between Ni crystallites and La2O3 support or La species which are decorating the Ni crystallites is responsible for the unusual chemisorptive and catalytic behaviour observed over the Ni/La2O3 catalyst.

280 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023140
2022230
2021100
2020103
201994
2018127