Sombut Panukorn, Puntscher Lena, Atzmueller Marlene, Jakub Zdenek, Reticcioli Michele, Meier Matthias, Parkinson Gareth S, Franchini Cesare
Institute of Applied Physics, TU Wien, 1040 Vienna, Austria.
Faculty of Physics, Center for Computational Materials Science, University of Vienna, 1090 Vienna, Austria.
Top Catal. 2022;65(17-18):1620-1630. doi: 10.1007/s11244-022-01651-0. Epub 2022 Jun 27.
The local environment of metal-oxide supported single-atom catalysts plays a decisive role in the surface reactivity and related catalytic properties. The study of such systems is complicated by the presence of point defects on the surface, which are often associated with the localization of excess charge in the form of polarons. This can affect the stability, the electronic configuration, and the local geometry of the adsorbed adatoms. In this work, through the use of density functional theory and surface-sensitive experiments, we study the adsorption of Rh, Pt, and Au metals on the reduced TiO(110) surface, a prototypical polaronic material. A systematic analysis of the adsorption configurations and oxidation states of the adsorbed metals reveals different types of couplings between adsorbates and polarons. As confirmed by scanning tunneling microscopy measurements, the favored Pt and Au adsorption at oxygen vacancy sites is associated with a strong electronic charge transfer from polaronic states to adatom orbitals, which results in a reduction of the adsorbed metal. In contrast, the Rh adatoms interact weakly with the excess charge, which leaves the polarons largely unaffected. Our results show that an accurate understanding of the properties of single-atom catalysts on oxide surfaces requires a careful account of the interplay between adatoms, vacancy sites, and polarons.
The online version contains supplementary material available at 10.1007/s11244-022-01651-0.
金属氧化物负载的单原子催化剂的局部环境在表面反应性和相关催化性能中起决定性作用。此类体系的研究因表面存在点缺陷而变得复杂，这些点缺陷通常与极化子形式的过量电荷的局域化相关。这会影响吸附原子的稳定性、电子构型和局部几何结构。在这项工作中，通过使用密度泛函理论和表面敏感实验，我们研究了Rh、Pt和Au金属在还原的TiO(110)表面（一种典型的极化子材料）上的吸附。对吸附金属的吸附构型和氧化态的系统分析揭示了吸附质与极化子之间的不同类型的耦合。如扫描隧道显微镜测量所证实的，Pt和Au在氧空位处的优先吸附与从极化子态到吸附原子轨道的强电荷转移相关，这导致吸附金属的还原。相比之下，Rh吸附原子与过量电荷的相互作用较弱，极化子基本不受影响。我们的结果表明，准确理解氧化物表面上单原子催化剂的性质需要仔细考虑吸附原子、空位和极化子之间的相互作用。
在线版本包含可在10.1007/s11244-022-01651-0获取的补充材料。
