论文标题
通过选择压力来调整PT负载Tio $ _2 $（110）上的SMSI动力学
Tuning SMSI Kinetics on Pt-loaded TiO$_2$(110) by Choosing the Pressure: A Combined UHV / Near-Ambient Pressure XPS Study
论文作者
论文摘要
可还原的氧化物支撑上的PT催化剂颗粒通常在高温下由于强大的金属支撑相互作用（SMSI）而显着改变其活性，从而诱导贵族金属颗粒周围的封装层的形成。然而，氧化和减少压力上的氧化和减少处理对该封装层的影响仍然存在争议，部分原因是表面科学研究与应用催化之间的“压力差距”。在目前的工作中，我们采用基于同步加速器的近气压X射线光电学光谱（NAP-XPS）来研究O $ _2 $和H $ _2 $对pt/Tio $ _2 $ _2 $ _2 $（110）催化剂的SMSI状态的效果。通过调整o $ _2 $压力，我们可以选择性地氧化Tio $ _2 $支持，或者既有支撑剂和PT颗粒。由金属PT催化，包裹的氧化物叠加剂在1x10 $^{ - 5} $ torr o $ $ _2 $中迅速生长，但是在较高的O $ _2 $压力下，pt的高度较小，其中PT处于氧化状态。尽管PT颗粒的氧化/还原是可逆的，但一旦发生封装，它们就会嵌入在支撑中。
Pt catalyst particles on reducible oxide supports often change their activity significantly at elevated temperatures due to the strong metal-support interaction (SMSI), which induces the formation of an encapsulation layer around the noble metal particles. However, the impact of oxidizing and reducing treatments at elevated pressures on this encapsulation layer remains controversial, partly due to the 'pressure gap' between surface science studies and applied catalysis. In the present work, we employ synchrotron-based near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) to study the effect of O$_2$ and H$_2$ on the SMSI-state of well-defined Pt/TiO$_2$(110) catalysts at pressures of up to 0.1 Torr. By tuning the O$_2$ pressure, we can either selectively oxidize the TiO$_2$ support or both the support and the Pt particles. Catalyzed by metallic Pt, the encapsulating oxide overlayer grows rapidly in 1x10$^{-5}$ Torr O$_2$, but orders of magnitudes less effective at higher O$_2$ pressures, where Pt is in an oxidic state. While the oxidation/reduction of Pt particles is reversible, they remain embedded in the support once encapsulation has occurred.
