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- Hossain, S., et al.
(författare)
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Highly dense and chemically stable proton conducting electrolyte sintered at 1200 °C
- 2018
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Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 43:2, s. 894-907
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Tidskriftsartikel (refereegranskat)abstract
- The BaCe 0.7 Zr 0.1 Y 0.2−x Zn x O 3−δ (x = 0.05, 0.10, 0.15, 0.20) has been synthesized by the conventional solid state reaction method for application in protonic solid oxide fuel cell. The phase purity and lattice parameters of the materials have been studied by the room temperature X-ray diffraction (XRD). Scanning electron microscopy (SEM) has been done for check the morphology and grain growth of the samples. The chemical and mechanical stabilities have been done using thermogravimetric analysis (TGA) in pure CO 2 environment and thermomechanical analysis (TMA) in Argon atmosphere. The XRD of the materials show the orthorhombic crystal symmetry with Pbnm space group. The SEM images of the pellets show that the samples sintered at 1200 °C are highly dense. The XRD after TGA in CO 2 and thermal expansion measurements confirm the stability. The particles of the samples are in micrometer ranges and increasing Zn content decreases the size. The conductivity measurements have been done in 5% H 2 with Ar in dry and wet atmospheres. All the materials show high proton conductivity in the intermediate temperature range (400–700 °C). The maximum proton conductivity was found to be 1.0 × 10 −2 S cm −1 at 700 °C in wet atmosphere for x = 0.10. From our study, 10 wt % of Zn seems to be optimum at the B-site of the perovskite structure. All the properties studied here suggest it can be a promising candidate of electrolyte for IT-SOFCs.
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| 2. |
- Rahman, Seikh M. H., et al.
(författare)
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Proton conductivity of hexagonal and cubic BaTi1-XScxO3-delta (0.1 <= x <= 0.8)
- 2014
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Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 43:40, s. 15055-15064
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Tidskriftsartikel (refereegranskat)abstract
- BaTi1-xScxO3-delta (X = 0.1-0.8) was prepared via solid state reaction. High resolution X-ray powder diffraction was used to characterise the synthesised materials. It was found that low substitution (x = 0.1 and 0.2) of Ti4+ for Sc3+ gives a hexagonal perovskite structure, whereas high substitution (x = 0.5-0.7) results in a cubic perovskite structure. Thermogravimetric analysis revealed significant levels of protons in both as-prepared and hydrated samples. Electrical conductivity was measured by AC impedance methods under oxygen, argon and under dry and humid, both H(2)0 and D2O, conditions for BaTi1-xScXO3-delta,(x = 0.2, 0.6 and 0.7). In the temperature range of 150-600 C-circle, under humid conditions, the conductivity is significantly higher than that under the dry conditions. The increase in conductivity is especially prominent for the cubic phases, indicating that protons are the dominant charge carriers. The proton conductivity of hexagonal BaTi0.8,Sc0.2O3-delta is approx. two orders of magnitude lower than that of the more heavily substituted cubic phases. Conductivity is also found to be higher in dry O-2 than in Ar in the whole temperature range of 150-1000 C-circle, characteristic of a significant contribution from p-type charge carriers under oxidising atmospheres. Greater Sc3+ substitution leads to a higher proton concentration and the highest proton conductivity (sigma similar to 2 x 10(-3) S cm(-1) at 600 degrees C) is found for the BaTi(0.3)Sc(07)cO(3-delta) composition.
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