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BaCe1 − xYxO3 − δ (BCY) and BaCe0.8 − yZryY0.2O3 − δ (BCZY) perovskite mixed metal oxides were synthesised by an aqueous sol-gel technique to be investigated for their suitability in intermediate-temperature catalytic applications such as Electrochemical Promotion of Catalysis. The hydration capacity and the stability under CO2 environments of the samples were studied using thermogravimetric analysis. Based on the evaluation of these properties, BaCe0.6Zr0.2Y0.2O3 − δ (BCZ20Y20) was selected as the membrane support for wireless Electrochemical Promotion for CO oxidation on Pt. In a dual-chamber reactor, the use of H2/H2O flow in the sweep side induced promoting species supply to the catalyst in the reaction side of the reactor. Moderate promotion of the catalytic rate up to 10% was observed for temperatures up to 650 °C, while this promotional effect was reversible and repeatable. The encouraging preliminary catalytic experiments together with the membrane's stability under the applied conditions reinforce the candidacy of BCZY membranes for intermediate-temperature applications in catalytic membrane reactors. [ABSTRACT FROM AUTHOR]

The use of microwave (MW) irradiation to assist the modified peroxide sol–gel synthesis of La1−xSrxMnO3 was shown to 1) improve crystallinity and 2) enhance the magnetic susceptibility and magnetocaloric effect (MCE) of samples compared to those synthesised using the conventional method. The improvement in crystallinity of the samples synthesised using MW irradiation was evident in the structural characterisation conducted using SEM and XRD. Magnetic heating experiments on La1−xSrxMnO3 (x = 0.25, 0.35 and 0.4) showed that for the MW-assisted method, the most suitable material for magnetic fluid hyperthermia applications was La0.65Sr0.35MnO3. MW settings (time and power) were investigated in an attempt to further optimise the MCE. Increasing MW time settings used (10 min, 30 min and 2 hours) led to increased saturation temperatures (45.9 °C, 57.0 °C and 58.3 °C, respectively), with a linear relationship between the MW power settings used and the MCE also observed during the magnetic heating experiments. Specific absorption rates as high as 175 W gMn−1 were achieved compared to the conventional maximum of 56 W gMn−1 in previous work. The enhancement of MCE was ascribed to a greater core ferromagnetic contribution as a result of the improvement in the degree of crystallinity and magnetic susceptibility of the samples synthesised with MW irradiation. [ABSTRACT FROM AUTHOR]

Abstract: The use of wireless electrochemical promotion of catalysis (EPOC) of a Pt catalyst supported on a mixed ionic electronic conducting hollow fibre membranes is investigated. This reactor configuration offers high surface areas per unit volume and is ideally suited for scaled-up applications. The MIEC membrane used is the La0.6Sr0.4Co0.2Fe0.8O3 perovskite (LSCF) with a Pt catalyst film deposited on the outer surface of the LSCF membrane. Experimental results showed that after initial catalyst deactivation (in the absence of an oxygen chemical potential difference across the membrane) the catalytic rate can be enhanced by using an oxygen sweep and wireless EPOC can be used for the in situ regeneration of a deactivated catalyst. [Copyright &y& Elsevier]

Abstract: Dense ceramics with mixed protonic–electronic conductivity are of considerable interest for the separation and purification of hydrogen and as electrochemical reactors. In this work, the hydrogen permeability of a Sr0.97Ce0.9Yb0.1O3− δ (SCYb) membrane with a porous Pt catalytic layer on the hydrogen feed-exposed side has been studied over the temperature range 500–804 °C employing Ar as the permeate sweep gas. A SiO2–B2O3–BaO–MgO–ZnO-based glass-ceramic sealant was successfully employed to seal the membrane to the dual-chamber reactor. After 14 h of exposure to 10% H2:90% N2 at 804 °C, the H2 flux reached a maximum of 33 nmol cm−2 s−1, over an order of magnitude higher than that obtained on membranes of similar thickness without surface modification. The permeation rate then decreased slowly and moderately on annealing at 804 °C over a further 130 h. Thereafter, the flux was both reproducible and stable on thermal cycling in the range 600–804 °C. The results indicate an important role of superficial activation processes in the flux rate and suggest that hydrogen fluxes can be further optimised in cerate-based perovskites. [Copyright &y& Elsevier]