Search results for "Electrolysis"

Reduction of ferricytochrome c catalyzed by optically active chromium(III) complexes

2009

The reduction rates of horse heart ferricytochrome c by amalgamated zinc or by electrolysis at fixed potential on a mercury pool as the cathode have been measured in a buffered solution at pH 7.5 by absorption spectrophotometry. In both cases, the reaction was strongly accelerated by the presence of the optically active complexes Lambda-[Cr(III)((S,S)-promp)H(2)O](+) (H(2)promp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]-bis[(S)-proline]), Delta-[Cr(III)((R,R)-alamp)H(2)O](+) (H(2)alamp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]-bis[(R)-alanine]) and Lambda-[Cr(III)((S,S)-alamp)(H(2)O)(2)](+). These were shown to undergo reversible one-electron reduction to the corresponding labile chromium(…

Sustainable electroorganic synthesis of lignin-derived dicarboxylic acids

2020

The oxidative ring opening of lignin-derived alkylated cyclohexanols to bio-based alkylated dicarboxylic acids is successfully performed by an electrocatalytic conversion. To establish this transformation as a green method, we developed a simple protocol for the anodic oxidation at nickel oxide-hydroxide (NiOOH) foam anodes in caustic soda in both a batch and flow electrolysis approach.

The Pd3(dppm)3(CO)2+ Cluster: An Efficient Electrochemically Assisted Lewis Acid Catalyst for the Fluorination and Alcoholysis of Acyl Chlorides.

2002

The dicationic palladium cluster Pd3(dppm)3(CO)2+ (dppm = bis(diphenylphosphino)methane) reacts with acid chlorides RCOCl (R = n-C6H13, t-Bu, Ph) to afford quantitatively the chloride adduct Pd3(dppm)3(CO)(Cl)+ and the acyl cation RCO+ as the organic counterpart. The dicationic reactive cluster can be reformed by electrolyzing the chloride complex with a copper anode leaving CuCl as a byproduct. The combination of these two reactions provides an electrocatalytic way to form the acylium from the acid chloride. Indeed, in CH2Cl2, 0.2 M NBu4PF6, or NBu4BF4, the electrolysis of the acid chloride in the presence of a catalytic amount of the cluster (1%) gives in good yields the acid fluoride RCO…

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…

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.

Design of a LLC Resonant Converter for Powering a PEM Electrolyzer

2021

International audience; This paper proposes the design of a LLC resonant converter to supply a proton exchange membrane (PEM) electrolyzer. The PEM requires a low voltage with high current, a reduced output voltage ripple, and an overdamped dynamic behavior of the converter to avoid voltage overshoots. The designed converter allows satisfying the design constraints, minimizing switching and reverse recovery losses; the efficiency is influenced mainly by the output rectifier's conduction losses.

Frontispiece: The “Green” Electrochemical Synthesis of Periodate

2020

New approaches for the effective valorization of papaya seeds: Extraction of proteins, phenolic compounds, carbohydrates, and isothiocyanates assiste…

2015

Abstract The study compares the efficiency of common aqueous extraction (CE) at different pH (2.5–11) and temperatures (20–60 °C) and extraction assisted by pulsed electric energy (pulsed electric fields, PEF or high voltage electrical discharges, HVED) of nutritionally valuable and antioxidant compounds from papaya seeds. The exponential decay pulses with initial electric field strengths of ≈ 13.3 kV/cm and ≈ 40 kV/cm for PEF and HVED treatments, respectively, were used. The number of pulses n was changed within 1–2000. The impacts of temperature and pH on extraction efficiency of different components (proteins, total phenolic compounds, carbohydrates, isothiocyanates) and antioxidant capa…

Electrodeposited nickel–zinc alloy nanostructured electrodes for alkaline electrolyzer

2022

Abstract Over the last decade, as a consequence of the global decarbonization process, the interest towards green hydrogen production has drastically increased. In particular a substantial research effort has focused on the efficient and affordable production of carbon-free hydrogen production processes. In this context, the development of more efficient electrolyzers with low-cost electrode/electrocatalyst materials can play a key role. This work, investigates the fabrication of electrodes of nickel-zinc alloys with nanowires morphology cathode for alkaline electrolyzers. Electrodes are obtained by the simple method of template electrosynthesis that is also inexpensive and easily scalable.…

Nanostructured Ni–Co alloy electrodes for both hydrogen and oxygen evolution reaction in alkaline electrolyzer

2021

Abstract Ni–Co alloy nanostructured electrodes with high surface area were investigated both as a cathode and anode for an alkaline electrolyzer. Electrodes were obtained by template electrosynthesis at room temperature. The electrolyte composition was tuned in order to obtain different NiCo alloys. The chemical and morphological features of nanostructured electrodes were evaluated by EDS, XRD and SEM analyses. Results show that electrodes with different composition of Ni and Co, made of nanowires well anchored to the substrate, were obtained. For both hydrogen and oxygen evolution reactions, electrochemical and electrocatalytic tests, performed in 30% w/w KOH aqueous solution, were carried…