Pt single atom catalysts anchored on the surface of anatase TiO₂ have recently been shown to be stable through oxidation and reduction conditions and exhibit higher catalytic activity in CO oxidation than Pt metallic clusters. In this work we unravel the atomistic nature of the isolated Pt_iso species on anatase TiO₂ thanks to the combination of CO probe molecule Fourier Transform Infrared (FTIR) and temperature programmed desorption (TPD) experiments with an extensive set of Density Functional Theory (DFT) calculations. We used the stretching frequencies and adsorption energies of CO bound to Pt as a fingerprint of the specific structure of the stable Pt_iso species. These consist of Pt atoms bound to two excess O atoms on the surface (PtO₂). The excess oxygen atoms on the surface arise from the formation of surface hydroxyl groups, and provide a solid anchor to the oxide support, which explains the high thermal stability of the single-atom Pt catalyst through oxidative and reductive treatments. Beside the single atom Pt species, also models of metallic, Pt_metal, and oxidized, Pt_ox, sub-nanometer clusters have been considered. Comparisons between characteristics of Pt_iso species and sub-nanometer Pt_metal and Pt_ox clusters demonstrate that the combination of CO vibrational frequency and adsorption energy can be an effective approach to differentiate these species.

最近已经证明，锚固在锐钛矿型TiO ₂表面上的Pt单原子催化剂在氧化和还原条件下是稳定的，并且在CO氧化中比Pt金属簇具有更高的催化活性。在这项工作中，我们将锐钛矿TiO ₂上分离的Pt _iso物种的原子性质解开了，这要归功于CO探针分子傅立叶变换红外（FTIR）和温度程序解吸（TPD）实验与广泛的密度泛函理论（DFT）的结合）计算。我们使用与Pt结合的CO的拉伸频率和吸附能作为稳定Pt _iso特定结构的指纹物种。这些由结合到表面上两个过量O原子（PtO ₂）的Pt原子组成。表面上过量的氧原子来自表面羟基的形成，并为氧化物载体提供了固体锚固，这说明了单原子Pt催化剂通过氧化和还原处理具有很高的热稳定性。除了单原子的Pt物种外，还考虑了金属，Pt_金属和氧化Pt _ox亚纳米簇的模型。Pt _iso物种与亚纳米Pt_金属和Pt _{ox的特性比较} 聚类表明，CO振动频率和吸附能量的组合可以成为区分这些物种的有效方法。