Abstract The double perovskites GdBaCo2O5.5 (GBCO) is candidate cathode materials for application in intermediate temperature solid oxide fuel cells (IT-SOFCs), attributing to excellent electrical conduction properties and oxidation activity. The electronic structure and the oxygen adsorption at BaO terminated surface of GBCO are investigated using projector augmented-wave (PAW) method based on spin-polarized density functional theory (DFT) with the inclusion of on-site Coulomb interaction. The BaO-terminated surface is adopted according to recent experimental results that this termination is energetically favorable for the double perovskites GBCO. We predict that G-AFM configuration is the most stable structure. The calculated results of oxygen vacancy energy indicate that the lowest energy vacancy positions are in the GdO layers. Charge transfer for the adsorbed oxygen and the surface ions is also examined by Bader charge analysis. The oxygen vacancies can facilitate oxygen adsorption and catalyze the bond cleavage. The existence of oxygen vacancy strengthens surface activity by acting as an active site at the surface. These results at the atomic level can contribute to the detailed understanding of oxygen reduction reaction mechanism.

中文翻译：

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GdBaCo2O5.5 的 BaO 封端表面的电子结构和氧吸附：第一性原理研究

摘要 双钙钛矿GdBaCo2O5.5（GBCO）具有优异的导电性能和氧化活性，是中温固体氧化物燃料电池（IT-SOFCs）的候选正极材料。使用基于自旋极化密度泛函理论 (DFT) 的投影仪增强波 (PAW) 方法研究了 GBCO 的 BaO 终止表面的电子结构和氧吸附，包括现场库仑相互作用。根据最近的实验结果，采用 BaO 终止的表面，该终止在能量上有利于双钙钛矿 GBCO。我们预测 G-AFM 配置是最稳定的结构。氧空位能的计算结果表明，最低能空位位置在 GdO 层中。吸附的氧和表面离子的电荷转移也通过巴德电荷分析来检查。氧空位可以促进氧吸附并催化键断裂。氧空位的存在通过充当表面的活性位点来增强表面活性。这些原子水平的结果有助于详细了解氧还原反应机理。