Exploring the Role of Zn in PdZn Reforming Catalysts: Adsorption and Reaction of Ethanol and Acetaldehyde on Two-dimensional PdZn Alloys

The adsorption and reaction of ethanol and acetaldehyde on two-dimensional PdZn alloys on Pd(111) were studied with use of temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS). Incorporation of Zn into the Pd(111) surface was found to decrease the dehydrogenation activity and alter the activation energies for C−H bond scission in adsorbed ethoxide, acetaldehyde, and acetyl intermediates. Large changes in the stability of adsorbed intermediates were observed on Zn/Pd(111) surfaces with Zn coverages <0.1 ML, indicating that long-range electronic effects play a role in altering the surface reactivity. The results obtained in this study are similar to those in our previous study of the reaction of methanol and formaldehyde on PdZn and further illustrate the dramatic effect that Zn substitution into the Pd lattice has on the reactivity of the surface.