Phase Transitions of Cobalt Oxide Bilayers on Au(111) and Pt(111): The Role of Edge Sites and Substrate Interactions

• DOI: 10.1021/acs.jpcb.7b04944
• Publication Date: 2017-08-11T19:25:46Z
• Authors: Jakob Fester; Zhaozong Sun; Jonathan Rodrígue...; Alex Walton; Jeppe V. Lauritsen
• Keywords: Cobalt oxide

Well-characterized metal oxides supported on single crystal surfaces serve as valuable model systems to study fundamental chemical properties and reaction mechanisms in heterogeneous catalysis or new thin film oxide catalysts their own right. Here, we present scanning tunneling microscopy X-ray photoelectron spectroscopy results for cobalt nanoislands that reveal the detailed atomistic leading transitions between Co-O bilayer O-Co-O trilayer, induced by oxidation O2 reductive vacuum annealing treatments, respectively. By comparing two different noble substrates, Au(111) Pt(111), further address influence of substrate. Overall, nanoisland edges act initiate both reduction processes substrates. However, important influences choice substrate were found, progress includes intermediate steps not observed where other hand takes place at a significantly higher rate. During treatment structure gradually reappears but rather appearance stacked morphology. These observations point strong differences catalytic behavior Au Pt oxides, despite otherwise structural similarities.