Abstract Density functional theory (DFT) calculations have been performed to determine the adsorption mechanism of Pt sub-monolayer (Θ ≤ 1 ML) on the positive BiFeO3 (0001) surface. We predicted that the adsorption behavior is different for Θ ≤ 1/2 ML and Θ > 1/2 ML based on detailed analysis of adsorption configuration, charge transfer effect, and orbital hybridization. For Θ ≤ 1/2 ML, there is only one type of Pt adatom site, which is binding directly with the low-lying O anion and shows electrons depletion/accumulation in the vertical/lateral 5d orbitals. For Θ > 1/2 ML, another type of Pt adatom site can be identified by not only the different adsorption configuration but also the distinct electronic states. Since the nearest neighbor of this type of Pt adatom site is the Bi cation, the charge transfer effect is characterized by significant electrons accumulation of the Pt-5d orbitals at the expense of the electron density of Bi cation. Another interesting feature occurs at Θ = 1 ML, i.e., the surface magnetic order displays ferromagnetic structure instead of antiferromagnetic arrangement. In addition, the existence of two types of Pt sites at Θ > 1/2 ML implies an intriguing possibility to enhance catalytic efficiency in the Pt/BFO (0001) heterocatalysis.

中文翻译：

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正 BiFeO3 (0001) 表面 Pt 亚单层吸附的 DFT 研究

摘要 已进行密度泛函理论 (DFT) 计算以确定 Pt 亚单层 (Θ ≤ 1 ML) 在正 BiFeO3 (0001) 表面上的吸附机制。基于对吸附构型、电荷转移效应和轨道杂化的详细分析，我们预测 Θ ≤ 1/2 ML 和 Θ > 1/2 ML 的吸附行为是不同的。对于 Θ ≤ 1/2 ML，只有一种类型的 Pt 吸附原子位点，它直接与低位 O 阴离子结合，并在垂直/横向 5d 轨道中显示出电子消耗/积累。对于 Θ > 1/2 ML，另一种类型的 Pt 吸附原子位点不仅可以通过不同的吸附构型来识别，还可以通过不同的电子态来识别。由于这种 Pt 吸附原子位点的最近邻是 Bi 阳离子，电荷转移效应的特点是 Pt-5d 轨道上的大量电子积累，以牺牲 Bi 阳离子的电子密度为代价。另一个有趣的特征出现在 Θ = 1 ML，即表面磁序显示铁磁结构而不是反铁磁排列。此外，在 Θ > 1/2 ML 处存在两种类型的 Pt 位点意味着在 Pt/BFO (0001) 杂催化中提高催化效率的有趣可能性。