Model studies on photocatalysis [Elektronische Ressource] : laser induced CO desorption from platinum nanoparticles at an alumina support / by Alaa Al-Shemmary

Model studies on photocatalysis: Laser induced CO desorption from platinum nanoparticles at an alumina supportin Partial Fulfillment of the Requirements for the DegreeDoctor in Natural SciencePresented to the Faculty of Mathematics and Scienceof Oldenburg University (Germany) byAlaa Al-Shemmaryin September 2010The first Referee: Prof. Dr. Katharina Al-ShameryThe second Referee: Prof. Dr. Thorsten KlünerDisputation day: 26.11.2010AbstractCO molecules adsorption has been studied at 90 K on different nanoparticles of platinum deposited via physical vapor deposition at 300 K ona n epitaxial alumina support grown on NiAl(110). Fourier transform infrared reflection absorption spectra have been recorded as a function of COcoverage and the amount of platinum deposited.T he CO adsorption is clearly assigned to on-top bonding when comparing the vibrational frequency to on-top CO on platinum single crystals. The CO vibrational frequency at saturation coverage increases linearly with the amount of the deposited platinum.TPD experiments show two species, the high temperature species are assigned adsorption at step-edge sites and the low temperature species to adsorption at the perimeter interface between t heplatinum particles and the alumina.Nanosecond laser excitation at λ = 355 nm have been used to produce Laser induced desorption ofCO adsorbed on platinum nanoparticles deposited on an epitaxial alumina support grown on NiAl(110).