Search results for "Electrolysis of water"
showing 10 items of 11 documents
Oxide anodes in electro-organic oxidation. Oxidation of maleic addon tungsten oxide anodes
1982
The electrochemical oxidation of maleic acid on tungsten anodes has been investigated. Glyoxal and carbon dioxide were the main products together with tartaric acid and acetaldehyde. Glyoxal is also obtained as the main product from the oxidation ofd-tartaric acid. Under the same conditions succinic acid is completely oxidized to carbon dioxide and water. The anodic dissolution of tungsten and the oxidation of water to oxygen become predominant in the final stages of the electrolyses.
A comparative evaluation of palladium and platinum nanoparticles as catalysts in proton exchange membrane electrochemical cells
2008
The goal of the present study is the development and comparative characterisation of carbon-supported and nanostructured Pd- and Pt-based electrocatalysts for hydrogen oxidation in Proton Exchange Membrane (PEM) H2/O2(air) fuel cells and proton reduction in PEM water electrolysers. Catalysts have been synthesised in a solution using a combined impregnation/reduction polyol method. They have been characterised using X-ray Diffraction (XRD) analysis, Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and cyclic voltammetry. NanoPt, nanoPd and nanoPt-Pd catalysts deposited onto a carbon carrier have been used to prepare Membrane-Electrode Assemblies (MEAs) which, in turn,…
Hydrogen from The Sea: The Challenge of the Future. Present and Future Developments
2014
In this paper we proposed the use of saline water to product hydrogen. As far as using saline water, can be proposed two different scheme and technology. The aim of this work is to design an electrolyze system capable of utilizing sea water for direct electrolysis. It is probable that these systems would operate at a low power density and electrolyze only a small portion of the water in contact with electrodes. In particular, we present the results obtained by two different prototype of electrolyzer: one with steel electrodes and the second electrodes with titanium. Further experiments were carried out by changing the electrolytic solution of water and sodium chloride in real seawater. Fina…
High-Performance Liquid Chromatographic Study on Oxidation Products of Lignin and Humic Substances
1991
We describe a convenient method of preparing samples and characterizing the mixture of degradation products obtained from alkaline cupric oxide oxidation of water samples containing lignin and humic substances. The method was applied to one unpolluted humic water sample and a total mill effluent of a kraft pulp mill. The fractions (Mr > 1000) obtained by ultrafi1tration were oxidized and the products (mixtures of degradation products) were analyzed by reversed-phase high-performance liquid chromatography (Spherisorb 5 ODS column). Acetonitrile-0.01 M phosphate buffer (pH 2) was used as the eluent in a gradient system and UV (set at 280 nm) as the detection system. Differences in the …
PEM electrolyzer characterization with carbon-based hardware and material sets
2021
Abstract The research and development of proton exchange membrane water electrolysis (PEMWE) is an upcoming and growing area due to a rising interest in hydrogen as an energy carrier. Operating conditions are harsher than in a fuel cell system, particularly because the potentials required for the oxygen evolution reaction are significantly higher. In commercial water electrolysis systems, this is compensated by typically using titanium material sets that are often protected against oxidation through coating processes. Such material choices make small scale research hardware and porous transport layers expensive and difficult to source. In this work, we show that the stability of traditional…
Reagent free electrochemical-based detection of silver ions at interdigitated microelectrodes using in-situ pH control
2021
Abstract Herein we report on the development of an electrochemical sensor for silver ions detection in tap water using anodic sweep voltammetry with in-situ pH control; enabled by closely spaced interdigitated electrode arrays. The in-situ pH control approach allowed the pH of a test solution to be tailored to pH 3 (experimentally determined as the optimal pH) by applying 1.65 V to a protonator electrode with the subsequent production of protons, arising from water electrolysis, dropping the local pH value. Using this approach, an initial proof-of-concept study for silver detection in sodium acetate was undertaken where 1.25 V was applied during deposition (to compensate for oxygen producti…
Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework.
2016
The synthesis of two molecular iron complexes, a dinuclear iron(III,III) complex and a nonanuclear iron complex, based on the di-nucleating ligand 2,2-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)(3)](3+). Funding Agencies|Knut and Alice Wallenberg Foundation; Swedish Research Council [621-2013-4872]; Carl Trygger Foundation; DFG (Metal Sites in Biomolecules: Structures, Regulation and Mechanisms) [IRTG 1422]; Swedish Energy Agency
Investigation of electrode material – redox couple systems for reverse electrodialysis processes. Part II: Experiments in a stack with 10–50 cell pai…
2013
Abstract The performances of reverse electrodialysis depend on several factors, including the nature of the electrode material and of the redox processes adopted to make possible the conversion between chemical potential and electric power. In this paper the possible utilization of various redox processes (reduction/oxidation of iron species, oxidation and reduction of water, oxidation of chlorine and reduction of water) was studied in a stack equipped with 10–50 cell pairs and by focused electrolyses in a three compartment cell. The effect of selected redox processes on power density output and eventual contamination of saline solutions flowing in the stack was evaluated in detail. The eff…
Fabrication and characterization of nanostructured Ni–IrO2 electrodes for water electrolysis
2014
Abstract Nanostructured Ni–IrO2 electrodes were fabricated by electrodeposition in a two-step procedure: first arrays of nickel nanowires (NWs) were electrodeposited within pores of polycarbonate (PC) membranes, then iridium oxide nanoparticles were deposited on the Ni metal after membrane dissolution, for improving the catalytic activity. The aim was to compare performance of these electrodes with traditional ones consisting of Ni film. Different methods of deposition of the IrO2 electrocatalyst were investigated and the effect on electrodes stability and activity is discussed. Despite a low coverage of Ni NWs by the electrocatalyst, results indicate a faster kinetics of O2 evolution in 1 …
Self-Radiolysis of Tritiated Water Stored in Zeolites 4A: Production and Behavior of H 2 and O 2
2015
International audience; Radiolysis of confined water and self-radiolysis of tritiated water give rise to several unanswered questions. To take into account this double specificity, we studied systems of zeolites 4A containing tritiated water at different water loading ratios. Two tritiated waters were synthesized at the volumetric activities of 27 and 60 TBq L −1. For each one, five samples were prepared, differentiated by their water loading ratios, expressed in percentage, close to 4%, 7%, 11%, 14%, and 19%. The study of the radiolysis in those systems revealed a double role of zeolites 4A: first, they increase the decomposition of water. Then they enhance the recombination of the major s…