Surface structure sensitivity of alloy catalysis: Catalytic conversion of n-hexane over Au-Pt(111) and Au-Pt(100) alloy crystal surfaces

Abstract

Alloys have become important catalysts for many chemical processes due to their superior properties over single component catalysts. These include increased reaction selectivity and greater resistance to deactivation. The reasons for their superior performance are not well understood, however. Catalytic studies, using single component metal single crystal catalysts, coupled with the use of surface science techniques, have proven useful in understanding the nature of the working catalyst. Extension of these investigations to alloy single crystal at high pressures should be useful for elucidating the role of alloying in altering catalytic behavior. In this note the authors report the surface structure sensitivity of the catalytic properties of platinum-gold alloys in the conversion reaction of n-hexane and present evidence for a mixed Au-Pt site on the (111) surface for the isomerization reaction. Experiments were carried out in an ultrahigh vacuum system equipped with Auger electron spectroscopy (AES), low energy electron diffraction (LEED) optics, a quadrupole mass spectrometer, and a sample isolation cell which was connected to the reactor loop and gas chromatograph equipped with a flame ionization detector. 11 references.