Yi Feng, Arlington Shane Q, Gorham Justin, Osborn William, Crumlin Ethan J, Nemsak Slavomir, LaVan David A
Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
Department of Materials Science, Johns Hopkins University, Baltimore, Maryland 21218, United States.
J Phys Chem Lett. 2022 Jul 7;13(26):6171-6176. doi: 10.1021/acs.jpclett.2c00343. Epub 2022 Jun 28.
The formation and thermal stability of Pt surface oxides on a Pt thin film were studied using ambient-pressure X-ray photoelectron spectroscopy. At an oxygen pressure of 73 Pa (550 mTorr), the surface Pt oxide was gradually formed, evidenced by the O 1s peak at 529.5 eV as the Pt film was heated. The Pt oxide peak reached a maximum between 217 and 317 °C and then decreased as the sample temperature was further increased. A similar response was seen on cooling from 480 to 23 °C; the intensity of the Pt oxide peak first increased and then decreased. The remaining Pt surface oxides partially decomposed during ultra-high-vacuum (UHV) pumping and completely decomposed during heating in UHV, which highlights the challenge of characterizing these surfaces with UHV instruments. These results have important implications for the understanding of the surface states of platinum films in different environments and the roles of different catalytic mechanisms.
采用常压X射线光电子能谱研究了铂薄膜上铂表面氧化物的形成及其热稳定性。在73 Pa（550 mTorr）的氧气压力下，随着铂薄膜被加热，表面铂氧化物逐渐形成，529.5 eV处的O 1s峰证明了这一点。铂氧化物峰在217至317 °C之间达到最大值，然后随着样品温度进一步升高而降低。从480 °C冷却至23 °C时也观察到类似的响应；铂氧化物峰的强度先增加后降低。在超高真空（UHV）抽气过程中，剩余的铂表面氧化物部分分解，在UHV加热过程中完全分解，这突出了使用UHV仪器表征这些表面的挑战。这些结果对于理解不同环境中铂薄膜的表面状态以及不同催化机制的作用具有重要意义。
