A new electrochemical cell with a uniformly accessible electrode to study fast catalytic reactions

International audienceThe electrochemical study of fast catalytic reactions is limited by mass transport when using the conventional electrochemical cell with a rotating disk electrode (RDE). To overcome this issue, it is important to find a new device with improved transport properties that respects electrochemical constraints. We used numerical simulations of computational fluid dynamics to design a new electrochemical cell based on the so-called “jet flow” design for the kinetic studies of catalytic chemical reactions at the surface of an electrode. The new cell is characterized by a high, reliable and uniform mass transport over the electroactive part of its surface. We investigated the effects of the nozzle and the electrode diameters, the nozzle–electrode distance and the Reynolds number on the performance of the jet-electrode in the flow system. Through the optimization of the geometry of this jet electrode cell, we achieved a factor of 3 enhancement in transport compared to the rotating disk electrode. We succeeded in constructing the designed electrode, characterized it with electrochemical techniques, and found an excellent agreement between the transport properties deduced from the numerical simulations and those from the measurements

Modelisation du couplage conduction-rayonnement par la methode des elements finis

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84595 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Optimizing the mass transport of wall-tube electrodes for protein film electrochemistry

International audienceProtein Film Electrochemistry (PFE) is a technique in which an enzyme is directly wired to an electrode and its catalytic turnover rate is measured under the form of an electrical current. This technique has proved useful for the study of a number of enzymes, but requires fast transport of the enzymatic substrate towards the electrode. In a previous work (Fadel et al, Phys. Chem. Chem. Phys., 2019, 21, 12360), we have proposed a new design based on the wall-tube electrode that provides better transport than the rotating disc electrode, which is usually employed for PFE studies. In the present work, we use computational fluid dynamics to explore the effects of the various parameters of the cell, and propose a semi-empirical formula suitable to predict the mass-transport coefficient and the wall shear stress on the electrode. We use a 3D-printed cell to experimentally validate our predictions

Enhancing Mass Transport in Jet Electrode to Study Highly Active Enzymes

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Modeling of coupled heat and mass transfers with phase change in a porous medium. Application to the superheated steam drying

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Open celled material structural properties measurement: from morphology to transport properties

International audienceMetallic foams are highly porous materials which present complex structure of three-dimensional open cells. The effective transport properties determination is essential for these widely used new materials. The aim of this work is to develop morphology analysis tools to study the impact of foams structure on physical transport properties. The reconstruction of the solid-pore interface allows the visualization of the 3D data and determination of specific surface and porosity. We present an original method to measure the geometrical tortuosity of a porous media for the two phases. A centerline extraction method allows us to model the solid matrix as a network of linear connected segments. The thermal conductivity of metallic foams is determined by solving energy equation over the solid phase skeleton. Results obtained on a set of nickel foams covering a wide range of pore size are discussed

Modélisation Des Transferts Dans Un Canal Poreux Parcouru Par Un Ecoulement Forcé De Pentane En Ebullition

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Enhancing Mass Transport in Jet Electrode to Study Highly Active Enzymes

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Enhancing mass transport in a new designed jet electrode to study the highly active enzymes

  CO-dehydrogenase [1-3] is a very promising enzyme for production of fuel from renewable resources by catalytic conversion of carbon dioxide. The knowledge of the catalysis mechanisms of this enzyme is highly important. Our group has studied the mechanism of this enzyme using protein film voltammetry (PFV) [1]. Unfortunately, the rotating disk electrode (RDE) classically used for these studies is almost useless due to the insufficient transport of the chemical species to match its very high activity; this blurs the enzymatic response and prevents mechanistic studies [4]. To overcome this issue, using numerical tools, a full extensive study of the mass transport of different configurations guided us to create new geometries of apparatus to improve and control the flow of species towards the electrode with the respect of our specific constraints imposed by theses enzymes

Amélioration du transport de masse dans les électrodes à jet pour l’étude des enzymes très actives

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