| AVS 60th International Symposium and Exhibition | |
| In Situ Spectroscopy and Microscopy Focus Topic | Thursday Sessions |
| Session IS+AS+SS-ThM |
| Session: | Ambient Pressure XPS from Sophistication to Reality |
| Presenter: | A. Baber, Brookhaven National Laboratory |
| Authors: | A. Baber, Brookhaven National Laboratory K. Mudiyenselage, Brookhaven National Laboratory S. Senanayake, Brookhaven National Laboratory J. Rodriguez, Brookhaven National Laboratory D. Stacchiola, Brookhaven National Laboratory |
| Correspondent: | Click to Email |
The importance of metal–oxide interfaces has long been recognized, but the molecular determination of their properties and role is only now emerging. Atoms with properties ranging from metallic to ionic are available at the metal–oxide interface and create unique reaction sites. We have shown that the activation of an efficient associative mechanistic pathway for the water–gas shift reaction by an oxide–metal interface leads to an increase in the catalytic activity of ceria nanoparticles deposited on Cu(111) or Au(111) by more than an order of magnitude. In situ near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) experiments demonstrated that a carboxy species formed at the interface is the critical intermediate in the reaction. To obtain a complete picture of the morphological and chemical changes occurring during catalytic processes, we investigated the reduction of Cu2O/Cu(111) under NAP of CO by a combination of in situ scanning tunneling microscopy (STM) and XPS to provide insight into the highly reducing environment of the water gas shift reaction on a model oxide surface. Systematic studies allow us to identify intermediate structures and determine how reaction fronts propagate across a surface with atomic scale resolution. Traditionally, STM is used to monitor surface structures and electronic properties, but here we show the surface oxide species can be identified with atomic-scale detail under near ambient pressures.