The Chemical Evolution of the La0.6Sr0.4CoO3−δ Surface Under SOFC Operating Conditions and Its Implications for Electrochemical Oxygen Exchange Activity

© The Author(s) 2018Owing to its extraordinary high activity for catalysing the oxygen exchange reaction, strontium doped LaCoO3 (LSC) is one of the most promising materials for solid oxide fuel cell (SOFC) cathodes. However, under SOFC operating conditions this material suffers from performance degradation. This loss of electrochemical activity has been extensively studied in the past and an accumulation of strontium at the LSC surface has been shown to be responsible for most of the degradation effects. The present study sheds further light onto LSC surface changes also occurring under SOFC operating conditions. In-situ near ambient pressure X-ray photoelectron spectroscopy measurements were conducted at temperatures between 400 and 790 °C. Simultaneously, electrochemical impedance measurements were performed to characterise the catalytic activity of the LSC electrode surface for O2 reduction. This combination allowed a correlation of the loss in electro-catalytic activity with the appearance of an additional La-containing Sr-oxide species at the LSC surface. This additional Sr-oxide species preferentially covers electrochemically active Co sites at the surface, and thus very effectively decreases the oxygen exchange performance of LSC. Formation of precipitates, in contrast, was found to play a less important role for the electrochemical degradation of LSC.Fonds zur Förderung der wissenschaftlichen Forschung (FWF)212921411

Thermochemical Hydrogen Storage via the Reversible Reduction and Oxidation of Metal Oxides

In this work, we perform a technical analysis of a cyclic reduction and oxidation process of metal oxides applied as a hydrogen storage route. Hydrogen is used to reduce a metal oxide and form steam, and regenerated by oxidizing the reduced metal oxide with steam. The reduced metal acts as the solid storage medium, which could be transported or used for stationary applications. Suitable metal oxides were screened according to the following performance indicators: specific energy demand (enthalpy change of reaction), thermodynamic conversion extents, specific storage density, resistance to sintering (melting point), and material cost. Iron oxide was then selected as the most promising candidate. A thermodynamic model was developed to determine favorable process temperatures of >400 °C for the hydrogen storage step and 100–500 °C for the hydrogen release step. The energy demand of the storage was calculated to be 27% of the lower heating value of hydrogen. Vis-a-vis other hydrogen storage methods, the iron-based storage exhibits drawbacks for on-board mobile applications but could be attractive for large-scale and long-term storage applications

Potential for energy production from agricultural and forest biomass in Ireland

SIGLEAvailable from British Library Document Supply Centre-DSC:OP-IRE/602 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Applications and limitations of two step metal oxide thermochemical redox cycles; a review

A critical review of thermochemical redox cycles as a means of converting heat to chemical energy and subsequent applications.</p

High redox performance of Y_0.5Ba_0.5CoO_3−δ for thermochemical oxygen production and separation

The efficient production and separation of oxygen is essential for numerous energy-intensive industrial applications in the fuel and mineral processing sectors.</p