Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780, Bochum, Germany.
Present address: CIC nanoGUNE, Tolosa Hiribidea 76, 20018, San Sebastián, Spain.
Angew Chem Int Ed Engl. 2018 Mar 19;57(13):3327-3331. doi: 10.1002/anie.201710791. Epub 2018 Feb 6.
Gold/titania catalysts are widely used for key reactions, notably including the selective oxidation of alcohols in the liquid phase. Our large-scale ab initio simulations disclose that the liquid-phase reaction mechanism is distinctly different from that in the gas phase because of active participation of water molecules. While concerted charge transfers related to O splitting and abstraction of both protonic and hydridic hydrogens are enforced under dry conditions, stepwise charge transfer is preferred in the condensed phase. Dissociation of reactive water molecules and subsequent Grotthuss migration of protonic defects, H (aq), allows for such a decoupling of the oxidation process, both in time and space. It is expected that these observations are paradigmatic for heterogeneous catalysis in aqueous phases.
金/二氧化钛催化剂被广泛应用于关键反应中，特别是包括醇的液相选择性氧化。我们的大规模从头算模拟揭示，由于水分子的积极参与，液相反应机制与气相中的机制明显不同。虽然在干燥条件下，与 O 分裂和质子和氢化物氢键的同时质子转移相关的协同电荷转移是强制性的，但在凝聚相中，分步电荷转移是首选的。反应性水分子的解离和随后质子缺陷 H(aq)的质子扩散迁移允许氧化过程在时间和空间上解耦。预计这些观察结果对于水相中的多相催化具有典范意义。
