Strong metal‐support interaction (SMSI) can be normally induced by the surface free energy differences between metal nanoparticles and supports. To gain deeper insights into the effect of SMSI on heterogeneous catalysis, we use prototype Pt, Pd/TiO2(anatase) systems to demonstrate different reverse water gas shift (RWGS) reaction activity changes, especially with increasing the metal nanoparticle (NP) loading. Our experiments show that the conventional surface‐free‐energy change law regarding the incremental NP size is no longer applicable to these systems, due to the overlook of the change of support properties owing to the disparities of the metal anchoring mechanisms. Both experimental measurements and DFT calculations show that Pt atoms strongly favor anchoring on the oxygen vacancies (Ov) over the OH‐sites on the anatase TiO2 support. In contrast, Pd atoms lack such Ov‐site preference compared to Pt atoms, thereby leaving higher content of Ov on the support than the Pt counterpart. Moreover, high density of residual Ov on the support can cause the Pd NPs to be in higher degree of contact with the support, either in NP‐encapsulation state (experiment) or NP‐spreading state (simulation). The enhanced CO2 conversion of Pt/TiO2A is attributed to the synergistic effect of Ov and hydrogen spillover from Pt sites.

中文翻译：

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揭开强金属-支持体相互作用形成的原因：金属纳米粒子锚定机制的差异


强金属-载体相互作用 （SMSI） 通常可以由金属纳米颗粒和载体之间的表面自由能差异诱导。为了更深入地了解 SMSI 对多相催化的影响，我们使用原型 Pt、Pd/TiO2（锐钛矿）系统来展示不同的反向水气转移 （RWGS） 反应活性变化，尤其是随着金属纳米颗粒 （NP） 负载的增加。我们的实验表明，由于金属锚固机制的差异而忽视了支撑特性的变化，因此关于增量 NP 尺寸的常规表面自由能变化定律不再适用于这些系统。实验测量和 DFT 计算都表明，Pt 原子强烈倾向于锚定在氧空位 （Ov） 上，而不是锐钛矿 TiO2 负载物上的 OH 位点。相比之下，与 Pt 原子相比，Pd 原子缺乏这种 Of 位点偏好，因此在载体上留下的 Ov 含量高于 Pt 对应物。此外，载体上高密度的残留 Ov 会导致 Pd NPs 与 载体的接触程度更高，无论是在 NP 封装状态（实验）还是 NP 扩散状态（模拟）。Pt/TiO2A 的 CO2 转化率增强归因于 Ov 和 Pt 位点氢溢出的协同效应。