Surface chemical state

Determination of surface chemical states of CoOj/TiOi catalysts for continuous wet TCE oxidation... 

Surface Chemical Analysis. Electron spectroscopy of chemical analysis (ESCA) has been the most useful technique for the identification of chemical compounds present on the surface of a composite sample of atmospheric particles. The most prominent examples Include the determination of the surface chemical states of S and N in aerosols, and the investigation of the catalytic role of soot in heterogeneous reactions involving gaseous SO2, NO, or NH3 (15, 39-41). It is apparent from these and other studies that most aerosol sulfur is in the form of sulfate, while most nitrogen is present as the ammonium ion. A substantial quantity of amine nitrogen also has been observed using ESCA (15, 39, 41). 

Yeong, S.H., Srinivasan, M.P., Colombeau, B., Chan, L., Akkipeddi, R., Kwok, C.T.M., Vaidyanathan, R. and Seebauer, E.G. (2007) Defect Engineering by Surface Chemical State in Boron-Doped Pre-amorphized Silcon. /. Appl. Phys., 91, 102112 (1-3). 

The use of CP-coated electrodes for metal electrodeposition, instead of the typical conducting (metal, glassy carbon etc.) substrates, results in the interference in this process of various specific factors that closely relate to the intrinsic propertiesof CPs. Among them are the initial oxidation state of the CP material, its surface morphology and surface chemical state, and also bulk characteristics, such as porosity and metal-polymer chemical interactions. These factors are often inter-related and therefore it is difficult to differentiate clearly their effect on the characteristics of the obtained metal deposit. 

Finally, recent investigations on mild UV-laser surface treatment of PEDOT layers [208,209] have shown that the surface chemical state of the polymer can become modified without any appreciable effect on the CP bulk properties. It was found [208] that UV-laser treatment results in activation of the surface with respect to metal nucleation and an increase in the number of dqjosited crystals by preserving a mono-disperse size distribution (Figure 7.7 c and d). 

We have just seen that the presence of a metal could have direct consequences on the nature of surface chemical states for an ionic oxide. 

Schaufuss AG, Nesbitt HW, Kartio I, Laajdehto K, Bancroft GM, Szatgan R (1998) Reactivity of surface chemical states on fractured pyrite. Siuf Sci 411 321-328 Schedel-Niedrig T, Weiss W, Schlogl R (1995) Electronic stracture of ultrathin ordered iron oxide films grown onto Pt (111). Phys Rev B 52 17449-17460... 

Depth-Related Composition and Surface Chemical State... 

The aforementioned nanoprobe and beam-based analyses results made clear the differences in surface roughness, mechanical/frictional properties, surface nanostructure, chemical composition, and surface chemical state on a nanometer scale between the MoDTC/ZDDP and ZDDP tribofilms. These results demonstrated that the nanostructural, nanometer-scale mechanical and chemical properties acted as the controlling factors in the macroscale friction behavior of the tribofilms. From these results, a microstructure model of the tribofilms was developed to explain the mechanism of friction reduction, as shown in fig. 9.20 [3, 34]. 

Biesinger MC, Payne BP, Grosvenor AP, Lau LW M, Gerson AR, Smart RSC (2011) Resolving surface chemical states in XPS analysis of first row transition metals, oxides and hydroxides Cr, Mn, Fe, Co and Ni. Appl Surf Sci 257 (7) 2717-2730... 

Returning to the problem of the surface chemical-state analysis of supported metal catalysts note that the particle size dependence of the BE should be known, or at least a reliable trend in it. There are different multitechnique ways of measuring it. The metal of interest can be evaporated or sputtered onto a flat substrate, for instance an oxidized Si wafer, a sapphire single crystal or pyrolytic graphite. Mean particle-size-related submonolayer coverages can then be estimated by quantitative XPS [36,37]. More directly, STM has been used to... 

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