Abstract

The activation of H₂ molecules by Pt₄ and Pt₃V clusters was studied by the nudged elastic band (NEB) DFT/PBE0/def2tzvp quantum chemical method with construction of minimum energy paths (MEPs). In the case of Pt₄ and Pt₃V clusters, barrier-free dissociative adsorption of H₂ molecules occurs at the platinum centers, while molecular adsorption of hydrogen occurs on the vanadium atom in Pt₃V with a slight weakening of the H−H bond, but without its breaking. The specific features of coordination of H₂ molecules are explained at the level of the MO method. Migration of the H atom from one cluster metal center to another in the model clusters (as probably in the case of hydrogen spillover) occurs at low activation barriers in the direction of the displacement vector corresponding to the normal vibrations of the system in the transition state. A significant role of Pt−H−Pt and V−H−Pt bridging groups in hydrogen migration has been revealed: they facilitate the transition of H atoms from one metal center of the cluster to another.

中文翻译：

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铂和铂钒簇上 H2 分子的活化：DFT 量子化学模型

摘要

通过构建最小能量路径（MEP）的微动弹性带（NEB）DFT/PBE0/def2tzvp量子化学方法研究了Pt 4_和Pt _{3 V团簇对H 2}分子的活化。_{在Pt 4}和Pt ₃ V簇的情况下，H ₂分子的无障碍解离吸附发生在铂中心，而氢的分子吸附发生在Pt ₃ V中的钒原子上，H−H略有减弱债券，但没有破裂。_{H 2}配位的具体特征分子在 MO 方法的水平上得到解释。H 原子从模型簇中的一个簇金属中心迁移到另一个簇金属中心（可能在氢溢出的情况下）发生在低活化势垒处，沿位移矢量方向对应于过渡态系统的法向振动。Pt−H−Pt 和 V−H−Pt 桥连基团在氢迁移中的重要作用已被揭示：它们促进氢原子从簇的一个金属中心过渡到另一个金属中心。