Dual-phase membranes are increasingly attracting attention as a solution for developing stable oxygen permeation membranes. CeGdO-FeCoO (CGO-F(3-x)CxO) composites are one group of promising candidates. This study aims to understand the effect of the Fe/Co-ratio, i.
View Article and Find Full Text PDFElectrochemical reduction of CO to value-added products holds promise for storage of energy from renewable sources. Copper can convert CO into multi-carbon (C ) products during CO electroreduction. However, developing a Cu electrocatalyst with a high selectivity for CO reduction and desirable production rates for C products remains challenging.
View Article and Find Full Text PDFStructural evolution, electrical conductivity, oxygen nonstoichiometry and oxygen transport properties of perovskite-type oxides La0.6A0.4FeO3-δ (A = Ca, Sr, and Ba) were investigated.
View Article and Find Full Text PDFCalcium manganite-based perovskite-type oxides hold promise for application in chemical looping combustion processes and oxygen transport membranes. In this study, we have investigated the structure, electrical conductivity and oxygen transport properties of perovskite-type oxides CaMn1-x-yTixFeyO3-δ. Distinct from previous work, data of high-temperature X-ray diffraction (HT-XRD) in the temperature range 600-1000 °C (with intervals of 25 °C) demonstrates that CaMnO3-δ (CM) transforms from orthorhombic to a mixture of orthorhombic and tetragonal phases between 875 °C and 900 °C.
View Article and Find Full Text PDFOne major challenge for the further development of solid oxide fuel cells is obtaining high-performance cathode materials with sufficient stability against reactions with CO present in the ambient atmosphere. However, the enhanced stability is often achieved by using material systems exhibiting decreased performance metrics. The phenomena underlying the performance and stability trade-off has not been well understood.
View Article and Find Full Text PDFOxygen surface exchange and diffusion in Pr1.75Sr0.25Ni0.
View Article and Find Full Text PDFThe incorporation of an organic group into sol-gel-derived silica causes significant changes in the structure and properties of these materials. Therefore, the thermal treatment of organosilica materials may require a different approach. In the present paper, kinetic parameters (activation energy, pre-exponential constant, and reaction models) have been determined from mass loss data for the dehydration, dehydroxylation, and decomposition reactions that take place upon heating silica and organosilica.
View Article and Find Full Text PDFWe present a theoretical and experimental study on the influence of the Ba/Sr and Co/Fe ratios as well as the oxygen-non-stoichiometry on the stability of Ba0.5Sr0.5Co0.
View Article and Find Full Text PDFZr0.84Y0.16O1.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2012
The oxygen surface exchange kinetics of mixed conducting perovskite oxides SrTi(1-x)Fe(x)O(3-δ) (x = 0, 0.01, 0.05, 0.
View Article and Find Full Text PDFModification of different zirconium propoxide precursors with H(2)dea was investigated by characterization of the isolated modified species. Upon modification of zirconium n-propoxide and [Zr(O(n)Pr)(O(i)Pr)(3)((i)PrOH)](2) with (1/2) a mol equivalent of H(2)dea the complexes [Zr(2)(O(n)Pr)(6)(OCH(2)CH(2))(2)NH](2) (1) and [Zr(2)(O(n)Pr)(2)(O(i)Pr)(4)(OCH(2)CH(2))(2)NH](2) (2) were obtained. However, (1)H-NMR studies of these tetranuclear compounds showed that these are not time-stable either in solution or solid form.
View Article and Find Full Text PDFWe demonstrate the use of a novel pulse (18)O-(16)O isotopic exchange technique for the rapid determination of the oxygen surface exchange rate of oxide ion conductors while simultaneously providing insight into the mechanism of the oxygen exchange reaction, which contributes to the efficient development of devices incorporating these solids, such as solid oxide fuel cells and oxygen transport membranes.
View Article and Find Full Text PDFThe modification of different zirconium propoxide and hafnium propoxide precursors with 2,2,6,6,-tetramethyl-3,5-heptanedione (Hthd) was investigated by characterization of the isolated modified species. The complexes [Zr(OnPr)3(thd)](2), [Zr(OnPr)(OiPr)2(thd)]2, Zr(OiPr)(thd)3, [Hf(OnPr)3(thd)]2, and Hf(OiPr)(thd)3 were isolated and characterized. The structure of the n-propoxide analogue of Zr(OiPr)(thd)3 could not be refined, but its existence was clearly demonstrated by XRD and 1H NMR.
View Article and Find Full Text PDFThe stabilizing and destabilizing mechanism in the action of acetylacetone on zirconium propoxide precursors is revealed; the nature of heteroleptic intermediates provides an explanation.
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