One-DimensionalPtO2at Pt Steps: Formation and Reaction with CO

Abstract

Using core-level spectroscopy and density functional theory we show that a one-dimensional (1D) oxide structure forms at the steps of the Pt(332) surface after exposure. The 1D oxide is found to be stable in an oxygen pressure range, where bulk oxides are only metastable, and is therefore argued to be a precursor to the Pt oxidation. As an example of the consequences of such a precursor exclusively present at the steps, we investigate the reaction of CO with oxygen covered Pt(332). Albeit more strongly bound, the oxidic oxygen is found to react more easily with CO than oxygen chemisorbed on the Pt terraces.

Surface sites on Pt–CeO2mixed oxide catalysts probed by CO adsorption: a synchrotron radiation photoelectron spectroscopy study

“…The binding energy of peak (F) in the C 1s region is consistent with assignment to CO adsorbed at on-top sites on metallic Pt particles. [33][34][35][36] Furthermore, the occurrence of peak (V) as a shifted component of peak (IV) is consistent with the core level shift due to CO adsorption. 35,36 In Fig.…”

Core-level shifts at the Pt/W(110) monolayer bimetallic interface

“…Using the relative kinetic energies of the Pt and bulk-W 4f7/2 features (35.86 ± 0.01 and 55.85 ± 0.01 eV, respectively), the difference in photon energies (20 eV), and the bulk-W 4f7/2 BE of 31.41 ± 0.01 eV [44], we obtain a BE of 71.40 ± 0.02 eV for ML Pt/W(110). Using reported values of the bulk Pt BE [45][46][47][48][49][50][51][52][53][54][55][56][57][58] we ascertain a value of 70.94 ± 0.08 eV for the BE of bulk Pt, yielding a core-level shift of +0.46 ± 0.09 eV for the Pt monolayer. We do not observe any shift in the Pt BE that might be associated with the transformation from the ps to the cp phase.…”

Oxidation and reduction of Pd(100) and aerosol-deposited Pd nanoparticles

“…One reason for this behavior could be that the particles contains a larger number of defects such as steps, kinks and corners which are sites considered as beneficial for oxidation [59]. Indeed, lately it has been observed that one dimensional oxides may easily form at steps at UHV conditions containing under coordinated atoms on vicinal surfaces [60,61]. In fact, it has been shown that the exact structure of the 1D oxide on the steps determines the rate of the continued growth of a 2D surface oxide [62].…”