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This work aims at investigating through a modeling approach the difference in thermal and electrochemical responses between high temperature H 2 O electrolysis and H 2 O+CO 2 co-electrolysis in solid oxide cells. The study has been conducted by considering a typical planar stack configuration with cathode supported cells. The influence of the local temperature on the polarization curve is discussed. Operating maps are simulated for both electrolysis modes depending on cell voltage and inlet gas flow rate, covering a complete range of gas conversion rates. The optimum domains of operating conditions combining high performances and reasonable temperature elevations are identified. In overall, higher performances are found in steam electrolysis. Indeed, the co-electrolysis process is found to be strongly limited by mass transport through the thick cathode. However, co-electrolysis exhibits an easier thermal management. Finally, the composition of the syngas produced by co-electrolysis is found to be highly flexible through adjustments of the operating parameters.

This work highlights an experimental and modeling approach devoted to a better understanding of H2O and CO2 co-electrolysis mechanisms at 800 °C. A standard Cathode Supported Cell (CSC) was used in this study. Through numerical adjustments on experimental polarization curves, the cathode microstructural parameters and exchange current densities for H2O and CO2 reductions were determined and subsequently implemented in an in-house co-electrolysis model. Additionally, micro gas chromatography (μGC) analyses were performed in co-electrolysis operating mode for different cell polarizations (from i = 0 to i = −1.75 A cm−2). μGC analyses at Open Circuit Voltage (OCV) were used to validate the kinetic constants of the Water Gas Shift (WGS) reaction implemented in the model. Predictions of both co-electrolysis polarization curves and outlet gas compositions were then compared to the experimental measurements. The good agreement between simulated and experimental data proves the relevance of the macroscopic representation of electrochemical processes through a “surface ratio” that takes into account the H2O and CO2 electrolyzes competition. A sensitivity analysis was performed to ensure a better understanding of co-electrolysis mechanisms and further investigate the influence of the reverse WGS reaction over CO production.

In this work, a comprehensive, predictive and quantitative model of a whole gas analyzer is provided in order to facilitate the design of such high performance devices. All the pre-analytical (gas separation) and analytical (detection and readout) stages have been modeled and experimentally calibrated. Heterogeneous simulations have been used to quantify the impact of the whole architecture on the output characteristic of the gas analyzer. Finally, the model of the NEMS sensor and the chromatography micro-column assembly has been experimentally validated with TEOX (toluene, ethylbenzene, octane, and xylene) gases.

An in-house micro model has been built to describe the electrochemical mechanisms governing both H2 and O2 electrodes operating in SOEC mode. A special attention has been paid to take into account the microstructure properties of the ionic, electronic and gas phases as well as the processes occurring therein. A commercial LSM–YSZ symmetrical cell has been tested at 700, 750 and 850 °C in air. Simulations have been carried out to interpret the experimental data. It is suggested that the kinetic of O2 formation is controlled by a single charge transfer. A sensitivity analysis has been performed using the micro model to quantify the role of the microstructure in the electrode behaviour. Transport of oxygen ions in the functional layer has a strong impact on the cell response since it governs the delocalization of the electrochemical reactions. The density of TPB length is also a key parameter controlling the electrode efficiency. Evolutions of the microstructural parameters in operation have been associated to the degradation of the electrochemical performances. The decrease in TPB length due to Ni agglomeration has a moderate impact whereas the decrease in ionic conductivities of 8YSZ or LSFC could explain a large amount of the cell degradation.

We report on silicon oxide deposited by direct photolysis at 185 nm of an N2OSiH4 mixture. Films are deposited at 250°C under a 665 Pa pressure on indium phosphide (InP). To determine the best insulator in terms of physico-chemical and electrical properties, the ratio R = SiH 4 N 2 O has been varied. A quasi-stoichiometric silicon oxide is obtained for R = 2% (O/Si = 1·87 instead of 2), the hydrogen and the nitrogen contents being, respectively, ≈15% and ≈5%. Electrical characterization has been done on Metal Insulator Semiconductor (MIS) diodes. After dipping InP in an (NH4)2SX solution, and after an appropriate annealing procedure, the density of states Nss is of the order of 1011 eV−1 cm−2. A quite good resistivity of 1015 ohm.cm is observed. Simple depletion mode Field Effect Transistors (MISFETs) are then made, and present a transconductance gm of 63 mS/mm and an Fmax of 20 GHz.

Fresh liver slices were shock-frozen in liquid nitrogen at −196°C, then powdered in a kitchen-mixer at the boiling temperature of the liquid nitrogen. The powdered liver was given to the larvae of a cyprinid hybrid fish (bighead carp × silver carp) in open-flow containers at 26–27°C. During the 3 weeks of feeding, growth and survival of the larvae were comparable with those of sibs fed living zooplankton.