| 研究実績の概要 |
Proton-conducting solid-oxide electrolysis and fuel cells represent viable, intermediate-temperature green energy conversion and storage technologies. However, their commercial viability has been hindered, in part, by the development of corresponding single-phase electrode components with mixed proton-electron conductivity (MPEC) and effective catalytic activity toward oxygen reduction and evolution reactions (ORR/OER). Also, the basic principles required to achieve high electronic conductivity accompanied by proton and oxygen-ion conduction are
poorly understood. This section of the work aims to understand the fundamental properties of these electrodes, like hydration, electronic
structure, conductivity, and catalytic activity. So far, the origin of catalytic activity in LnCo0.5Ni0.5O3-δ (Ln=La, Pr and Nd) perovskites
"positrodes" (positive electrode) were investigated by low energy-ion scattering (LEIS), hydration and DFT studies. LEIS results reveal that La, Pr, Nd, and Pr cations dominate the outer atomic layer, with profound implications for catalytic activity. Whereas the First principal calculations performed using the plane-wave DFT method and hybrid HSE06 functional suggest the catalytic activity and electronic properties depend on the valence shell structure of the Ln-site cation and their redox properties.
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| 今後の研究の推進方策 |
By employing deuterium as a tracer indicator, proton formation and transport were observed on the surface and bulk of some materials like BaGd0.8La0.2Co2O6-δ (BGLC), La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and Ba0.5La0.5CoO3-δ (BLC). However, to fully understand the underlying principles of ionic transport in these oxides, additional spectroscopic studies are required to reveal their electronic properties, the spin state of constituent cations, their coordination, and changes while the oxide is being exposed to water vapor. From now on, I will focus on using X-ray absorption spectroscopy (XAS) realized in both near-edge and extended ranges (if possible) to further understand the dependence between elemental compositions and their electron configuration. Detailed near-edge feature analysis will be performed to obtain
information on the oxidation state and changes in the electronic structure of all elements upon hydration.
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| 次年度使用額が生じた理由 |
The present amount is what was left over and carried forward due to project extension and will be used for research expenditure, beam line
payment.
The purchase of items such as, high-grade chemical reagents for material synthesis, High purity gases, platinum lead wires, equipment
maintenance
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