Les métamorphoses, entre fiction et notion

Centré sur la représentation des métamorphoses naturelles, ce volume se propose d’étudier des échanges croisés entre fiction et science, dans une perspective transséculaire et interdisciplinaire. Il développe une réflexion sur les potentialités épistémologiques et esthétiques de l’idée de métamorphose, et cherche à mettre en lumière les enjeux idéologiques, philosophiques ou religieux, qui se rattachent à cette notion du xvie au xxie siècle

Oxidation behavior of H2 and CO produced by H2O and/or CO2 reduction in molten carbonates: Effect of gas environment and hydroxides

International audienceCo-electrolysis of water and carbon dioxide in molten carbonates is nowadays a key issue in MCEC (molten carbonate electrolysis cell) and, reversely, for a better understanding of MCFC (molten carbonate fuel cell). The products of water and carbon dioxide reduction are the fuels that might be used in MCFC or other energy devices. The present study is dedicated to a thorough electrochemical investigation by voltammetric techniques (Cyclic Voltammetry CV or Linear Sweep Voltammetry LSV) at a Pt electrode of such fuels in Li2CO3-K2CO3 eutectic, under varied atmosphere conditions, including partial pressures of H2O, CO2, H2 and Ar at 650°C. The conditions of formation of soluble and/or adsorbed H2 and CO are established together with qualitative thermodynamics information on the redox systems involved. C is only detected in very specific conditions. Knowing that hydroxides, produced in the conditions of MCEC and MCFC, have a significant role on the operation of such devices, an electrochemical analysis (CV and impedance measurements) of the effect of added amounts of hydroxides is developed for the first time, showing the enhancement of oxidation currents and the progressive increase in electrolyte conductivity

Atomic Layer Deposition, a Key Technique for Processing Thin-Layered SOFC Materials - Case Of Epitaxial Thin Layers of CeO2 Catalyst

International audienc

Mixtures of room temperature ionic liquid/ethanol solutions as electrolytic media for cerium oxide thin layer electrodeposition

International audienceA cerium oxide thin layer was electrodeposited onto stainless steel, using mixed room temperature ionic liquid (the 1-methyl-3-butylimidazolium bis(trifluoromethyl sulfonyl)imide)/ethanol solutions, as electrolytic medium. The hydrophobic ionic liquid content is one of the main parameters in the morphology control influencing the ceria growth rate and crystallinity. Micro-nano structural properties and electrical behaviour are presented, using XRD, SEM/EDS and impedance spectroscopy, as a function of electrodeposition conditions

Input on the Measurement and Comprehension of CO2 Solubility in Molten Alkali Carbonates in View of Its Valorization

As the capture and valorization of CO2 in molten carbonates is nowadays becoming a strategic energy topic, the need of accurate solubility measurements of such molecule is becoming compulsory. This study provides a new set of reliable CO2 solubility values, determined by a a carefully adapted manometric setup, in Li2CO3-K2CO3 (62:38 mol%), Li2CO3-Na2CO3 (52:48 mol%), Li2CO3-Na2CO3-K2CO3 (43.5:31.5:25.0 mol%) and Na2CO3-K2CO3 (56:44 mol%) carbonate eutectics in an overall range of temperatures from 450 to 850 °C. High solubility values are obtained for Li-K and Li-Na eutectics, respectively 1.7 × 10-1 and 1.1 × 10-1 mol atm-1 l-1 at 650 °C. It is shown that CO2 solubility increases with the temperature for most of the eutectic mixtures. Another important trend is that the Li content significantly increases the solubility. © 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited

Diagnosis of a cathode-supported solid oxide electrolysis cell by electrochemical impedance spectroscopy

High-temperature electrolysis (HTSE) is a quite recent topic where most of the studies are focused on performance measurements and degradation observations, mainly achieved by polarization curve. However, it mainly leads to the overall cell behaviour. To get more specific knowledge on the operation of the cell, Electrochemical Impedance Spectroscopy (EIS) is more appropriate. In this study, EIS and chronopotentiometry were combined in order to characterize the electrochemical performance and behaviour of a commercial electrode-supported cell of Ni-YSZ/YSZ/LSCF type. A two-electrode configuration was used while a three-electrode one is required to better separate each component behavior. Nevertheless, it allows applying EIS to any single cell mainly when no good location for a reference electrode is available. Experimental parameters such as current density, temperature or PH2O/PH2 ratio were analysed. Using electrical equivalent circuit (EEC) combined to the distribution of relaxation time (DRT) and the analysis of the difference in impedance spectra (ADIS) approaches allowed deconvoluting impedance diagrams into three or four arcs characterized by their specific capacitance and relaxation frequency. Each arc was ascribed to a phenomenon related to the electrochemical reactions. This work corresponds to an in situ diagnosis by EIS of solid oxide electrolyser cell reaction mechanisms.FIabilisation De l'ELectrolYse de l'eau à haute température pour la production d'Hydrogèn

Synthesis and characterization of LaNixCo1−xO3: Role of microstructure on magnetic properties

International audienc