Oxygen adsorption, labeled

While we have focused here on the oxygen adsorption at the electrode surface, in the following, we will discuss the part of the phase diagram shaded gray and labeled Oxide formation in Fig 5.10b. 

Labelled Oxygen Adsorption. When five milliliters of oxygen labelled with a trace of 0-15 were injected onto the Pennsylvania anthracite, about 5% was retained on the column at low temperature. All of this oxygen was desorbed during the heating cycle. When a mixture of labelled O2, CO2 and H2O labelled with 0-15 in proportions of 80 15 5 in 5 cc of nitrogen was injected onto the column with no added carrier (approximately 10 molecules of O2 due to ppm impurities of 0-16, 02), all of the activity was retained on the column. When 1 cc of O2 was added to the mixture only activities which corresponded to CO2 and H2O were retained on the column. When 1 cc of a 50 50 mixture of CO2 and O2 was added only about 5% of the activity was retained on the column. This activity probably corresponds to the water activity. 

Fig. 4.5 a, b Oxygen exposure dependence of the He-I photoelectron spectra at the successive stages of oxygen adsorption on polycrystal Cu surface (reprinted with permission from [9]). Two apparent features K (—1.5 eV) and D (—6 eV) are similar to those appeared in other oxide surfaces, c PES of cleaved crystal of O-Cu(OOl) valence band spectral features recorded at 70 eV energy. Labeled energies indicate the DOS features (reprinted with permission from [18])... 

Temperature programmed reaction spectra depicting the reaction of H2O and OH groups with oxygen on Pd(lOO) are shown in fig. 3. Curve (a) was obtained for H2O adsorption on the clean surface and contains two peaks, the state at 167 K of multilayer H2O, and the <>2 state at 182 K due to H2O bound directly to the surface /7/. An additional state at 255 K, labelled y, is observed following coadsorption of 1 0 and 0 (fig. 3b). This state represents the reaction of OH groups III... 

In this work the methanol and methyl iodide conversion and their co-reaction are investigated on Fe-Beta zeolite without any oxygen. Partly Fe-ion-exchanged Beta-300 i.e. Fe-H-Beta-300 (shortly Fe-Beta-300) zeolite keeps the light acidity to a certain extent, however the presence of Fe ions (as transition metal, Fe is an excellent Lewis acid) can modify the reaction pathway. This Fe-Beta-300 has been tested already by low temperature peat pyrolysis [6], At present, the adsorption as well as desorption of methanol are followed-up by radiodetectors using ( -radioisotopic labeling [4, 7]. The... 

Fig. 23. IRAS spectra of CO2 adsorbed on Cr203(0001) surfaces and on polycrystalline chro-mia, left panel IRAS spectra at different surface temperatures and with isotopically labeled CO2 as well as Cr203, right panel adsorption of CO2 after pre-adsorption of oxygen [112].

Figure 2.3. Surface complexation phenomena in the retention or desorption of metals from mineral surfaces. Nonspecific (exchangeable) adsorption consists of electrostatic bonds only and the ions retain their hydration sphere (outer-sphere complexes) specific (nonexchangeable) adsorption requires removal of the hydration sphere (inner-sphere complexes). Alkali and alkaline earth metals tend to form outer-sphere complexes, hence their tendency to be loosely bound and readily exchangeable with other ions in solution. Transition metals tend to form inner-sphere complexes, which are more strongly bound and less exchangeable (Cotter-Howells and Paterson, 2000). Representation of (a) an outer-sphere complex, (b) an inner-sphere complex, and (c) a solution complex (see also Figure 2.2). The solid substrate is textured with the solution above this. Unlabeled spheres represent oxygen atoms, and the spheres labeled M represent metals in the substrate or in solution. Smaller shaded spheres labeled H are hydrogen atoms. (Adapted from Brown et al., 1999 Cotter-Howells and Paterson, 2000.)...

Fig. 3.1 The optimized ground-state structures of SiQDs. The silicon, carbon, hydrogen, and oxygen atoms are cyan, gray, white, and red, respectively. The three different adsorption positions are labeled by number 1, 2, or 3 in (a) and (b) [22]. Reprinted with permission from (Li QS, Zhang RQ, Niehaus TA, Frauenheim T, Lee ST (2007) Theoretical studies on optical and electronic properties of propionic-acid-terminated sdicon quantum dots, J Chem Theory Comput 3 1518-1526). Copyright (2007), American Chemical Society...

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