In heterogeneous catalysis, the interaction between reactant molecules and the surface of the catalyst often causes changes in the surface composition and chemical state of the catalyst, which, in turn, may affect its reactivity. Therefore, it is important to systematically characterize such interactions using well-controlled model systems with in situ techniques such as ambient pressure XPS. Pt-Cu single atom alloys (SAA), in which Pt forms highly dispersed, isolated atoms, have recently gained increased interest as an active hydrogenation catalyst. In this talk, I will present recent AP-XPS results from the 23-ID-2 (IOS) beamline at the National Synchrotron Light Source II in which we studied the interaction of common reactants (CO, H<sub>2</sub>, O<sub>2</sub>) with the Pt/Cu(111) SAA model system. By directly probing the Pt 4f core level, we were able to clearly distinguish Pt atoms in different environments (adsorbate-bound surface Pt, free surface Pt, subsurface Pt) and monitor their evolution in the presence of various gases in order to gain a fundamental understanding of the surface properties and behavior of this system in reaction conditions.

In situ surface characterization of Pt-Cu single atom alloy model system in ambient pressure of gases

256th National Meeting (2018)

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