X-Ray photoelectron spectroscopy characterization

X-ray photoelectron spectroscopy characterization of catalysts was performed on a VG ESCA LABMKII X-ray photoelectron spectrograph under a vacuum of 10 Pa. Mg Ka ray was used as excitation source hv = 1253.6 eV). Cis was used as the internal standard to calibrate the binding energy results. 

D.B. Cairns, S.P Armes, M.M. Chehimi, C. Permchot, and M. Delamar, X-ray photoelectron spectroscopy characterization of submicrometer-sized polypyrrole - Polystyrene composites, Langmuir, 15(23), 8059-8066 (1999). 

Losito, I., Amorisco, A., Pahnisano, F. and Zambonin, P.G. 2005. X-ray photoelectron spectroscopy characterization of composite Ti02-poly(vinyhdenefluoride) films synthesised for applications in pesticide photocatalytic degradation. Annl. Surf. Sci. 240(1-4) ... 

Tidwell, C.D., Castner, D.G., Golledge, S.L., Ratner, B.D., Meyer, K., Hagenhoff, B., Benninghoven, A. (2001) Static time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy characterization of adsorbed albumin and fibronectin films. Surf. Interface Anal, 31,724-733. 

Yamauchi Y, Sakurai T, Hirohata Y, Hino T, Nishikawa M (2002) Blue shift of photoluminescence spectrum of porous silicon by helium ion irradiation. Vacuum 66(3-4) 415—418 Zanoni R, Righini G, Mattogno G, Schirone L, Sotgiu G, Rallo F (1999) X-ray photoelectron spectroscopy characterization of stain-etched luminescent porous silicon films. J Lumin 80 159-162... 

X-ray photoelectron spectroscopy (XPS) is among the most frequently used surface chemical characterization teclmiques. Several excellent books on XPS are available [1, 2, 3, 4, 5, 6 and 7], XPS is based on the photoelectric effect an atom absorbs a photon of energy hv from an x-ray source next, a core or valence electron with bindmg energy is ejected with kinetic energy (figure Bl.25.1) ... 

M. Peuckert, and H.P. Bonzel, Characterization of oxidized platinum surfaces by X-ray photoelectron spectroscopy, Surf. Sci. 145, 239-259 (1984). 

A catalyst supported on y-AFO was prepared from Re2Pt(CO)i2l (Fig. 70) and characterized by IR. X-ray photoelectron spectroscopy (XPS), and TPR. The chemi.sorbed cluster was treated with H2 at about 150 C resulting in fragmentation and formation of rhenium subcarbonyls at 400 C the sample was completely decarbonylated. A catalyst prepared from a mixture of Re3(//-H)3(CO)i2l and PtMe2(// -cod)] and treated under equivalent conditions showed the rhenium to... 

Several spectroscopic, microscopic and diffraction techniques are used to investigate catalysts. As Fig. 4.2 illustrates, such techniques are based on some type of excitation (in-going arrows in Fig. 4.2) to which the catalyst responds (symbolized by the outgoing arrows). For example, irradiating a catalyst with X-ray photons generates photoelectrons, which are employed in X-ray photoelectron spectroscopy (XPS) -one of the most useful characterization tools. One can also heat a spent catalyst and look at what temperatures reaction intermediates and products desorb from the surface (temperature-programmed desorption, TPD). 

The films were characterized using x-ray powder diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The photoelectron spectroscopy utilized a Vacuum Generators ESCA Lab II system with Mg(Ka) radiation. Binding energies (BE) were measured with respect to the surface C(ls) peak (284.5 eV) which was always present In these films. Scanning electron microscopy was done with a JEOL JSM-35C system. 

In the present study, we synthesized in zeolite cavities Co-Mo binary sulfide clusters by using Co and Mo carbonyls and characterized the clusters by extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and high resolution electron microscopy (HREM). The mechanism of catalytic synergy generation in HDS is discussed. 

Usually bimetallic nanoparticles as well as monometallic ones are characterized by many probing tools such as UV-visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), EXAFS, infrared spectroscopy of adsorbed CO (CO-IR), and so on [1,2]. 

Size reduction of metal particles results in several changes of the physico-chemical properties. The primary change is observed in the electronic properties of the metal particles which can be characterized by ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS, respectively) as well as Auger-electron spectroscopy (AES) measurements. Furthermore, morphology of the metal nanoparticles is highly sensitive to the environment, such as ion-metal interaction (e.g. metal-support interaction)... 

Most suitable for the examination of the surface is x-ray photoelectron spectroscopy, whereas the wettability determination can be established by a detailed interpretation of core flooding experiments and wettability index measurements. The results of such studies show that the organic carbon content in the surface is well correlated with the wetting behavior of the material characterized by petrophysical measurements [1467,1468]. 

The structure of [Ir2dcbmi(CO)4] (424) is reported.680 The binuclear compounds were all oxidized around +0.1 V vs. SCE, with the oxidation potential dependent on the solvent.681 Oxidation of [NBu4][Ir2(dcbmi)(CO)4] results in growth of a conducting film on the surface. The partially oxidized material [NBu4]0.5[Ir2(dcbmi)(CO)4] has been characterized by X-ray photoelectron spectroscopy. 

X-ray photoelectron spectroscopy (XPS) of electrodes was first applied to the oxidation of noble metal electrodes. Kim and Winograd investigated in 1971 the electrochemical formation of anodic oxides on Pt [10] and later on Au electrodes [60]. The electrochemical parameters of oxide formation on these noble metal electrodes were well characterized and enabled a direct correlation between ex situ XPS and in situ electrochemical analysis. 

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