Date of Award
1996
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
Fourier transform infrared (FTIR) spectroscopic studies of adsorbates on metal surfaces have been carried out using FTIR reflection-absorption spectroscopy, synchotron radiation FTIR and time-resolved FTIR, along with Auger electron spectroscopy, low energy electron diffraction, thermal desorption spectroscopy, nuclear reaction analysis and work function change. For water on hex and (1 x 1) Pt(100), clustering takes place readily at low temperature from the lowest coverages, and a small number of large clusters tend to form. On Pt(100) containing Si impurity, clusters are initially nucleated at impurity sites and tend to be smaller and more numerous. For H{dollar}\sb2{dollar}O/Al(100) at T {dollar}<{dollar} 130 K, a distribution of relatively small clusters exists. At coverages under 0.35 ML on Ni(110), water adsorbs monomerically at 85-180 K, and the H{dollar}\sb2{dollar}O wagging and rocking modes can be observed in the far IR.;On both stepped Ni(760) and Ni(110), the saturation coverage for the first chemisorbed layer is 0.5 ML (ML = {dollar}1.15\times10\sp{lcub}15{rcub}{dollar} molecules cm{dollar}\sp{lcub}-2{rcub}){dollar} and no FTIR activity (1000-4000 cm{dollar}\sp{lcub}-1{rcub}){dollar} is observed until the coverage exceeds 0.5 ML. Less water exists in the A{dollar}\sb1{dollar} desorption state on Ni(760) compared with D{dollar}\sb2{dollar}O/Ni(110). At temperatures above 398 K, water is observed to autocatalytically dissociate on clean Ni(760), forming H{dollar}\sb2{dollar}(g) and O(ads). Ni(760) appears to be much more reactive than Ni(110), resulting in a significantly higher reaction probability. A (2 x 1)-O phase is formed upon completion of the reaction, corresponding to an absolute oxygen coverage of 0.3-0.4 ML depending on the reaction temperature.;A fast time-resolved Fourier transform spectroscopy (FTRFTS) system has been developed for obtaining reflection IR data on surfaces with microsecond time resolution. Laser induced thermal desorption is a suitable method for modulating the CO coverage on a Pt surface. Conversion of linearly bonded to bridge bonded CO can be observed in thermal transients, suggesting that the species are not in equilibrium at room temperature. The FTRFTS system has been used for the first time to obtain FTIR-RAS spectra of CO on Pt(111).
Recommended Citation
Kasza, Rita Violet, "Ftir Spectroscopic Studies Of Adsorbates On Metal Surfaces" (1996). Digitized Theses. 2703.
https://ir.lib.uwo.ca/digitizedtheses/2703