The selective oxidation of crotyl alcohol to crotonaldehyde over ultrathin Au overlayers on Pd(1 1 1) and Au/Pd(1 1 1) surface alloys has been investigated by time-resolved X-ray photoelectron spectroscopy (XPS) and mass spectrometry. Pure gold is catalytically inert towards crotyl alcohol which undergoes reversible adsorption. In contrast, thermal processing of a 3.9 monolayer (ML) gold overlayer allows access to a range of AuPd surface alloy compositions, which are extremely selective towards crotonaldehyde production, and greatly reduce the extent of hydrocarbon decomposition and eventual carbon laydown compared with base Pd(1 1 1). XPS and CO titrations suggest that palladium-rich surface alloys offer the optimal balance between alcohol oxidative dehydrogenation activity while minimising competitive decomposition pathways, and that Pd monomers are not the active surface ensemble for such selox chemistry over AuPd alloys. Crown
Bibliographical noteWe thank the EPSRC (EP/D038359/1 and EP/E046754/1), and acknowledge support by the EC-Research Infrastructure Action under the FP6 ‘‘Structuring the European Research Area’’ Programme (through the Integrated Infrastructure Initiative ‘‘Integrating Activity on Synchrotron and Free Electron Laser Science’’). SFJH and JN thank the EPSRC for the award of studentships.