Search results for "Redox"
showing 10 items of 619 documents
Temperature dependence of oxidation behavior and coercivity evolution in fine-grained spinel ferrites
2000
Abstract The present paper reviews for a series of fine-grained MxCoyFe(3−x−y)O4 spinel ferrites (M=Mn, Mo, Cu, V) which oxidize into mixed-valence defect ferrites, a systematic study of the correlation between the oxidation temperature and the variation of coercivity. An increase of the coercivity is observed as often as the oxidation reactions Fe2+→Fe3+ and Mn+→M(n+m)+ (1⩽m⩽3) occur. This enhancement of coercivity has been explained by stresses generated during each specific oxidation reaction. The well-known property of cobalt to strongly magnify the magnetostrictive effects has been used to support this interpretation.
Performance analysis of single cell solid oxide fuel cells
2017
Solid oxide fuel cells (SOFCs) are a class of fuel cells operating on high temperatures which have the potential to become one of the efficient and cost effective system for direct conversion of a wide variety of fuels to electricity. For proper operation of SOFCs, evaluation of cell stability and optimization of fuel utilization is of paramount importance. In this paper, we have performed experiments to obtain current-voltage (I–V) characteristics by using three different Hydrogen (H 2 ) flow rates(100 ml/min, 150 ml/min and 200 ml/min). Furthermore, we perform oxidation and reduction (redox) cycles to determine how many redox cycles a SOFC can withstand without cracking the cell which we …
‘Maya chemistry’ of organic–inorganic hybrid materials: isomerization, cyclicization and redox tuning of organic dyes attached to porous silicates
2013
[EN] Association of indigo and lapachol dyes to aluminosilicate clays yields polyfunctional organic – inorganic hybrid materials forming Maya Blue-like systems. Upon partial removing of clay's zeolitic water by moderate thermal treatment, abundant isomerization, cyclicization and oxidation reactions occur defining a‘ Maya chemistry whose complexity could explain the versatile use of such materials in the pre-Columbian cultures and permits the preparation of polyfunctional materials potentially usable for therapeutic and catalytic purposes.
Essential oils as natural additives to prevent oxidation reactions in meat and meat products: A review
2018
Oxidation reactions during manufacturing, distribution, and storage of meat and meat products result in undesirable physicochemical changes and aromas, which leads to detrimental effects on the product quality. This could be translated into the consumer dissatisfaction and economic loss. One of the most common practices to overcome this issue is the incorporation of synthetic antioxidants. However, the increasing health-consciousness of consumers and their preference for natural additives leads to the search of natural alternatives to synthetic antioxidants. A number of essential oils have strong antioxidant properties and are explored as potential alternatives to chemical antioxidants in t…
Heterogeneous Photocatalysis and Photoelectrocatalysis: From Unselective Abatement of Noxious Species to Selective Production of High-Value Chemicals
2015
Heterogeneous photocatalysis and photoelectrocatalysis have been considered as oxidation technologies to abate unselectively noxious species. This article focuses instead on the utilization of these methods for selective syntheses of organic molecules. Some promising reactions have been reported in the presence of various TiO2 samples and the important role played by the amorphous phase has been discussed. The low solubility of most of the organic compounds in water limits the utilization of photocatalysis. Dimethyl carbonate has been proposed as an alternative green organic solvent. The recovery of the products by coupling photocatalysis with pervaporation membrane technology seems to be a…
Exploiting redox activity of MIL-100(Fe) carrier enables carvacrol prolonged antimicrobial activity
2021
The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing foodborne illnesses. In this work, we develop a smart composite MOF-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural preserving food molecule, carvacrol, into the mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method and obtaining particularly high payloads. By exploiting the intrinsic redox nature of MIL-100(Fe) material it is possible to achieve a prolonged activity against E. coli bacteria due to a triggered two-step carvacrol release of films…
Chemical and electrochemical behaviour of 4,4’,4’’,4’’’-tetrakis(dimethylamino)-tetraphenylethylene in an oxidant environment: Toward a new sensor fo…
2020
Abstract Electrochromic compounds are suitable candidates for being used in sensor design. Here we report the use of 4,4’,4’’,4’’’-tetrakis(dimethylamino)-tetraphenylethylene for detecting both NO2 and SO2. Whereas the sensing mechanism in the case of nitrogen dioxide is a simple chemical oxidation reaction, in the case of sulfur dioxide, the mechanism is much more complex and the reaction requires the presence of t-butylhydroperoxide to take place. By modifying the detection conditions both compounds can be detected in gas phase. Additionally, a wide electrochemical study has been carried out to understand the role played by the t-butylhydroperoxide in the reaction with sulfur dioxide.
Gold(ii) in redox-switchable gold(i) catalysis
2019
Chemical communications 55(32), 4615 - 4618 (2019). doi:10.1039/C9CC00283A
Multielectron transfer in a dicopper(II) anthraquinophane.
2013
The new dinuclear copper(II) metallacyclophane with the non-innocent N,N'-1,4-bis(oxamate)-9,10-anthraquinone bridging ligand possesses a dual multielectron redox behavior featuring stepwise one-electron oxidation of the antiferromagnetically coupled Cu(II) ions and two-electron reduction of the anthraquinone spacers in a π-stacked anti conformation.
Mitochondrial dynamics in type 2 diabetes: Pathophysiological implications
2017
Mitochondria play a key role in maintaining cellular metabolic homeostasis. These organelles have a high plasticity and are involved in dynamic processes such as mitochondrial fusion and fission, mitophagy and mitochondrial biogenesis. Type 2 diabetes is characterised by mitochondrial dysfunction, high production of reactive oxygen species (ROS) and low levels of ATP. Mitochondrial fusion is modulated by different proteins, including mitofusin-1 (MFN1), mitofusin-2 (MFN2) and optic atrophy (OPA-1), while fission is controlled by mitochondrial fission 1 (FIS1), dynamin-related protein 1 (DRP1) and mitochondrial fission factor (MFF). PARKIN and (PTEN)-induced putative kinase 1 (PINK1) partici…