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Ca2Fe1.95Mg0.05O5: Innovative low cost cathode material for intermediate temperature solid oxide fuel cell
No full textThe good oxygen ion conductivity makes brownmillerites suitable as electrode materials for SOFCs. In this contribution, we focus on Ca2Fe1.95Mg0.05O5 (CFMO) with the idea of evaluating this brownmillerite as a promising innovative and low-cost cathode material. The synthesis was made through citrate route, where a magnesium doping was carried out to emphasize Fe3+/Fe4+ redox couple and thus the electronic conductivity. The chemical and physical properties of the material were verified by XRD, H2-TPR, XPS, BET and SEM techniques. The material was electrochemically characterized as a cathode by EIS, obtaining promising ASR values (0.19 Ωcm2 at 800 °C). Furthermore, CFMO stability under different atmosphere conditions was confirmed by EIS investigation at different oxygen partial pressures. The material was activated by deposition of FeOx nanoparticles through co-deposition and infiltration; the effect of increasing amount (10 and 15 wt %) was also studied. The Ca2Fe1.95Mg0.05O5 based nanocomposites well perform as cathode materials and the electrocatalytic reduction of oxygen is enhanced by iron oxide. This is confirmed by a reduction of ASR to 0.17 Ωcm2 at 800 °C for CFMO with Fe2O3 15 wt % as the best result of the study
Synthesis and characterization of Ca2Fe1.95Mg0.05O5: innovative low cost material for Reversible Solid Oxide Cell
No full textThermalization with a multibath: an investigation in simple models
No full textWe study analytically and numerically a couple of paradigmatic spin models, each described in terms of two sets of variables attached to two different thermal baths with characteristic timescales T and τ and inverse temperatures B and β. In the limit in which one bath becomes extremely slow ( τ → ∞ ), such models amount to a paramagnet and to a one-dimensional ferromagnet in contact with a single bath. Our study is also motivated by analogies with disordered systems where widely separated timescales associated with different effective temperatures emerge. We show that these systems reach a stationary state in a finite time for any choice of B and β. We determine the non-equilibrium fluctuation-dissipation relation between the autocorrelation and the response function in such a state and, from that, we discuss if and how thermalization with the two baths occurs and the emergence of a non-trivial fluctuation-dissipation ratio
Different activation of CuO nanoparticles on La0.8K0.2MO3 (M=Cr,Mn) perovskites: oxygen exchange interaction between metal and support material
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CuO/La0.5Sr0.5CoO3: Precursor of efficient NO reduction catalyst studied by: Operando high energy X-ray diffraction under three-way catalytic conditions
Full text linkSubstitution of critical raw materials such as platinum group metals in automotive catalysts is challenging. In this work we prepared a nanocomposite in which CuO nanoparticles are highly dispersed on a La0.5Sr0.5CoO3 perovskite-type oxide. The behaviour and reactivity under three way catalyst conditions was monitored by operando time-resolved high-energy X-ray diffraction under oscillating rich/lean feed. The reducing environment converted CuO into Cu(0) in a two step process: Cu(ii) to Cu(i) and to Cu(0), while the perovskite evolved to an oxygen deficient brownmillerite phase. These structural transformations are shown to be crucial for catalytic activity. The in situ generated Cu(0)/Cu(i)/brownmillerite nanocomposite is active for NO reduction above 300 °C, reaching 90% NO conversion at 450 °C. The effect of feed composition on the diffraction patterns was studied by Rietveld refinement in order to rationalize the experimental observations under TWC conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
SrTiO3-based perovskites: developing economic and robust materials for sustainable development
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