The Interaction of K and O on Au(111): Multiple Growth Modes of Potassium Oxide and Their Catalytic Activity for CO Oxidation.

In industrial catalysis, alkali cations are frequently used to promote activity or selectivity. Scanning tunneling microscopy, ambient-pressure X-ray photoelectron spectroscopy, and density-functional calculations were used to study the structure and reactivity of potassium oxides in contact with the Au(111) surface. Three different types of oxides (K O , K O and KO with y<0.

Surface structure of mass-selected niobium oxide nanoclusters on Au(111).

The structures formed by the deposition of mass-selected niobium oxide clusters, NbO( = 5, 6, 7), onto Au(111) were studied by scanning tunneling microscopy. The as-deposited NbOclusters assemble into large dendritic structures that grow on the terraces as well as extend from the top and bottom of step edges. The NbOcluster also forms dendritic assemblies but they are generally much smaller in size.

Surface characterization and methane activation on SnO/CuO/Cu(111) inverse oxide/metal catalysts.

To activate methane at low or medium temperatures is a difficult task and a pre-requisite for the conversion of this light alkane into high value chemicals. Herein, we report the preparation and characterizations of novel SnO/CuO/Cu(111) interfaces that enable low-temperature methane activation. Scanning tunneling microscopy identified small, well-dispersed SnO nanoclusters on the CuO/Cu(111) substrate with an average size of 8 Å, and such morphology was sustained up to 450 K in UHV annealing.

Growth and structural studies of In/Au(111) alloys and InO/Au(111) inverse oxide/metal model catalysts.

Indium oxide has received attention as an exciting candidate for catalyzing the CO hydrogenation to methanol due to its high selectivity (>80%). Compared to the extent of research on the activity of indium oxide-based powder catalysts, very little is known about the phenomena associated with the formation of surface alloys involving indium or the growth mechanism for indium oxide nanoparticles. In this report, scanning tunneling microscopy and X-ray photoelectron spectroscopy (XPS) were employed to elucidate the growth mode, structure, and chemical state of In/Au(111) alloys and InO/Au(111) inverse model catalysts.