Photoelectron metal oxide surfaces

Figure 19. Photoelectron spectra of CO adsorbed on metal and metal oxide surfaces in comparison with gaseous and condensed CO The spectra are taken m normal electron emission.

In this paper, we focus on the structure and properties of PLL-g-PEG-modified surfaces as well as on the adsorption kinetics of PLL-g-PEG onto metal oxide surfaces. We present the results of surface investigations using reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS), and time-of-flight sec-... 

The focus of the present chapter is i) on the application of X-ray Photoelectron spectroscopy (XPS) to the investigation of metal oxides surfaces (both in form of powder as well as of thin films) and ii) on the wide spectrum of different single, multicomponent and composite oxide systems which can be thoroughly studied from the point of view of composition and chemical nature of the species (oxidation state, chemical environment, electronic structure). 

Solomon, E.I., Jones, P.M., and May, J.A. Electronic structures of active sites on metal oxide surfaces definition of the Cu/ZnO methanol synthesis catalyst by photoelectron spectroscopy. Chem. Rev. 1993, 93, 2623-2644. 

Abstract This chapter explores the manner in which the surface analysis methods of X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) can be used to extract information regarding the interfacial chemistry of adhesion from polymer/metal systems such as adhesive joints. It will be shown that the analysis of a failure interface is an uncertain method to extracting interface chemistry but in certain situations, where a very thin layer of polymer remains on the metal oxide surface, this provides spectra characteristic of the interphase. In most situations, some form of chemical or mechanical sectioning is necessary, and microtomy and dissolution methods are described as ways in which chemical information at high depth resolution can be extracted from the interphase zone. 

An example of a spectrum with a chemical shift is that of the tin 3d peaks in Eig. 2.8. A thin layer of oxide on the metallic tin surface enables photoelectrons from both the underlying metal and the oxide to appear together. Resolution of the doublet 3 ds/2, 3 dii2 into the components from the metal (Sn ) and from the oxide Sn " is shown in Eig. 2.8 B. The shift in this instance is 1.6-1.7 eV. Curve resolution is an operation that can be performed routinely by data processing systems associated with photoelectron spectrometers. 

Surface analysis has made enormous contributions to the field of adhesion science. It enabled investigators to probe fundamental aspects of adhesion such as the composition of anodic oxides on metals, the surface composition of polymers that have been pretreated by etching, the nature of reactions occurring at the interface between a primer and a substrate or between a primer and an adhesive, and the orientation of molecules adsorbed onto substrates. Surface analysis has also enabled adhesion scientists to determine the mechanisms responsible for failure of adhesive bonds, especially after exposure to aggressive environments. The objective of this chapter is to review the principals of surface analysis techniques including attenuated total reflection (ATR) and reflection-absorption (RAIR) infrared spectroscopy. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and secondary ion mass spectrometry (SIMS) and to present examples of the application of each technique to important problems in adhesion science. 

In the present study the surface chemistry of birnessite and of birnessite following the interaction with aqueous solutions of cobalt(II) and cobalt(III) amine complexes as a function of pH has been investigated using two surface sensitive spectroscopic techniques. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). The significant contribution that such an investigation can provide rests in the information obtained regarding the chemical nature of the neat metal oxide and of the metal oxide/metal ion adsorbate surfaces, within about the top 50 of the material surface. The chemical... 

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