Surface infrared spectroscopy

A novel high surface area heterogeneous catalyst based on solution phase colloidal nanoparticle chemistry has been developed. Monodisperse platinum nanoparticles of 1.7−7.1 nm have been synthesized by alcohol reduction methods and incorporated into mesoporous SBA-15 silica during hydrothermal synthesis. Characterization of the Pt/SBA-15 catalysts suggests that Pt particles are located within the surfactant micelles during silica formation leading to their dispersion throughout the silica structure. After removal of the templating polymer from the nanoparticle surface, Pt particle sizes were determined from monolayer gas adsorption measurements. Infrared studies of CO adsorption revealed that CO exclusively adsorbs to atop sites and red-shifts as the particle size decreases suggesting surface roughness increases with decreasing particle size. Ethylene hydrogenation rates were invariant with particle size and consistent with a clean Pt surface. Ethane hydrogenolysis displayed significant structure sensitivi...

Hydrothermal growth of mesoporous SBA-15 silica in the presence of PVP-stabilized Pt nanoparticles: synthesis, characterization, and catalytic properties.

The influence of surface defects on the infrared spectra of adsorbed species

Alkali-metal-affected adsorption of molecules on metal surfaces

Electron-stimulated desorption: Principles and applications

An infrared reflection-absorption study of CO chemisorbed on clean and sulfided Ni(111) — Evidence for local surface interactions

Temperature dependence of the vibrational lineshape of CO chemisorbed on the Ni(111) surface

Electrostatic effects between adsorbed species—the K … Co interaction on Ni(111) as studied by infrared reflection-absorption spectroscopy

By using the bond direction imaging capabilities of the electron stimulated desorption ion angular distribution (ESDIAD) technique, we have observed a thermally induced azimuthal disorder effect due to the thermal population of unbound hindered rotor states in chemisorbed PF3 on Ni(111). The six beam F+ ESDIAD patterns observed for PF3 on Ni(111) are interpreted as evidence for a weak barrier that hinders the rotation of isolated PF3 molecules on the Ni(111) surface. At a coverage of ∼0.04 PF3/Ni, a barrier to rotation of ∼80±20 cm−1 is estimated from the observed temperature dependence of the F+ ESDIAD patterns using a two‐dimensional hindered rotor model. The PF3 coverage dependence of the thermally induced azimuthal disorder effect indicates that intermolecular forces are responsible for an increase in the hindering potential at high PF3 coverages.

The direct observation of hindered rotation of a chemisorbed molecule: PF3 on Ni(111)

Interactions between chemisorbed CO and oxygen on Ni(111)

K. J. Uram

Papers

An infrared reflection-absorption study of CO chemisorbed on clean and sulfided Ni(111) — Evidence for local surface interactions

Temperature dependence of the vibrational lineshape of CO chemisorbed on the Ni(111) surface

Electrostatic effects between adsorbed species—the K … Co interaction on Ni(111) as studied by infrared reflection-absorption spectroscopy

The direct observation of hindered rotation of a chemisorbed molecule: PF3 on Ni(111)

Interactions between chemisorbed CO and oxygen on Ni(111)