The performance of coated and bonded aluminium relies heavily upon its surface chemistry and hence characterization of the aluminium surface is important. A method to quantify the hydroxide concentration at aluminium oxide/hydroxide surfaces by curve fitting the O 1s peak is developed and tested in this paper.Pseudoboehmite, AlO(OH), is formed at the surface of aluminium after immersion in boiling water. The surface of this material was used to determine the binding energy of the unresolved O 1s component peaks that were referenced to the binding energy of the Al 2p oxide component. In vacuo heating resulted in changes in the elemental and functional composition that were consistent with dehydration of the pseudoboehmite. It is proposed that the resultant film comprises g-alumina with residual hydroxide groups.The O 1s curve-fitting method was applied to air-formed films with known atmospheric exposure histories before and after heating in vacuo. The change in both the elemental composition and functional stoichiometry of the films upon heating was consistent with significant but incomplete dehydration. The probable surface phases are determined from the functional and elemental composition.

No abstract

A total of 43 polymers containing only C, H, and O have been studied using an X-ray photoelectron spectroscopy Instrument capable of the highest energy resolution available to date. The primary aim was to reinvestigate the C1s binding energy shifts for oxygen functionalities and to systematically Investigate secondary (ß) shifts for the first time. In addition, this large data set has revealed the effects of vibrational fine structure on C1s component line wldth/shape and the effects of shake-up/shake-off (In photoemlsslon from C=0 groups) on nonstoichiometry of C1s component Intensities.

No abstract

Oxide films grown anodically at the surface of superpure aluminium are used as standards to assess the accuracy of the thickness (d XPS ) determined using the Beer-Lambert treatment of the Al 2p metal and oxide peak intensities. For the fitting conditions employed, the value of d XPS is found to be very close to the true film thickness for films <10 nm thick, beyond which imprecise values are obtained. A surface layer of hydration is identified from the curve fitting of the O 1s core level, which would qualitatively account for the slight underestimate of film thickness provided by the expression for d XPS . The validity of the Al 2p fit may be determined through this correlation of thickness but requires first a quantitative assessment of the thickness and composition of the hydroxide-rich layer.

No abstract

The influence of plasma oxidation and other surface pretreatments on the electronic structure of indium–tin–oxide (ITO) thin films has been studied by high resolution x-ray photoemission spectroscopy. Plasma oxidation compensates n-type doping in the near surface region and leads to a reduction in the energy of plasmon satellite structure observed in In 3d core level spectra. In parallel, the Fermi level moves down within the conduction band, leading to a shift to low binding energy for both core and valence band photoemission features; and the work function increases by a value that corresponds roughly to the core and valence band binding energy shifts. These observations suggest that the conduction band of ITO is fixed relative to the vacuum level and that changes of work function are dominated by shifts of the Fermi level within the conduction band.

Recyclable, heterogeneous bimetallic ruthenium/molybdenum catalysts, formed in situ from triruthenium dodecacarbonyl [Ru 3 (CO) 12 ] and molybdenum hexacarbonyl [Mo(CO) 6 ], are effective for the selective liquid phase hydrogenation of cyclohexylcarboxamide (CyCONH 2 ) to cyclohexanemethylamine (CyCH 2 NH 2 ), with no secondary or tertiary amine by-product formation. Variation of Mo:Ru composition reveals both synergistic and poisoning effects, with the optimum combination of conversion and selectivity at ca. 0.5, and total inhibition of catalysis evident at ! 1. Good amide conversions are noted within the reaction condition regimes 20-100 bar hydrogen and 145-160 8C. The order of reactivity of these catalysts towards reduction of different amide functional groups is primary > tertiary @ secondary. In situ HP-FT-IR spectroscopy confirms that catalyst genesis occurs during an induction period associated with decomposition of the organometallic precursors. Ex situ characterisation, using XRD, XPS and EDX-STEM, for active Mo:Ru compositions, has provided evidence for intimately mixed ca. 2.5-4 nm particles that contain metallic ruthenium, and molybdenum (in several oxidation states, including zero).