Proton incorporation and trapping in ZrO2 grain boundaries
Proton incorporation and trapping in ZrO2 grain boundaries
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DOI：
10.1039/c3ta14029f
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发表时间：
2014-01-01
影响因子：
11.9
通讯作者：
Tanaka, Isao
中科院分区：
文献类型：
--
作者：
Dawson, James A.;Tanaka, Isao
使用原子模拟技术计算 ZrO2 晶界中的水结合和质子-掺杂剂缔合的能量，即 Sigma 5(310)/[001] 和 Sigma 5(210)/[001]，并与立方块体材料获得的结果进行比较。原子间势集是根据最适合实验数据的基础从文献中可用的那些中选择的。立方体 ZrO2 的计算水合能和氧化还原反应能都很高，与实验一致。相比之下，晶界内及其周围氧离子的水合能要低得多，而氧化还原能也显着降低。 ZrO2 中受体掺杂剂和质子之间的强结合能表明存在显着的质子捕获。虽然结合（质子捕获）在晶界结构中仍然普遍存在，但结合能通常较小，这表明如果发生质子传导，它最有可能沿着晶界而不是块体材料发生。研究发现，较小离子（如 Sc）的结合最强，而较大离子（如 Gd 和 La）的结合较弱。还对两种晶界结构的结果进行了比较，并评估了质子迁移的后果。
The energetics of water incorporation and proton-dopant association in ZrO2 grain boundaries, namely Sigma 5(310)/[001] and Sigma 5(210)/[001], are calculated using atomistic simulation techniques and are compared to results obtained for the cubic bulk material. The interatomic potential set was chosen from those available in the literature on the basis of the best fit to experimental data. Both the calculated hydration energy and the redox reaction energies for cubic bulk ZrO2 are shown to be high, in agreement with the experiment. In contrast, the hydration energies for oxygen ions in and around the grain boundaries are far lower, while the redox energies are also significantly reduced. Strong binding energies between acceptor dopants and protons in bulk ZrO2 suggest significant proton trapping. While binding (proton trapping) is still prevalent in the grain boundary structures, the binding energies are generally smaller suggesting that should proton conduction occur it is most likely to occur along the grain boundaries rather than the bulk material. Binding is found to be the strongest for smaller ions like Sc and weaker for larger ions like Gd and La. Comparisons between the results for the two grain boundary structures are also made and the consequences for proton migration are assessed.