Role of Atomic Step Defect Sites on the Catalytic Oxidation of Carbon Monoxide: Comparison between Ru(001) and Ru(109) Single-Crystal Surfaces

摘要

A comparison of the reactivity of chemisorbed oxygen with chemisorbed CO on Ru(109) and Ru(001) surfaces to produce CO2 shows that the atomically stepped Ru(109) surface provides active oxygen species, whereas the Ru(001) surface is inactive. Using Auger spectroscopy and low-energy electron diffraction, it is found that the activity of Ru(109) is caused by the local high oxygen coverages achieved at the Ru step sites where the O/Ru ratio is 1.3 ± 0.3. The O/Ru(109) surface, saturated with CO, produces an inhomogeneous CO layer as observed by infrared spectroscopy, whereas O/Ru(001) produces a single terminally bound CO species.