Surfaces property changes

The knowledge of the surface potential for the dispersed systems, such as metal oxide-aqueous electrolyte solution, is based on the model calculations or approximations derived from zeta potential measurements. The direct measurement of this potential with application of field-effect transistor (MOSFET) was proposed by Schenk [108]. These measurements showed that potential is changing far less, then the potential calculated from the Nernst equation with changes of the pH by unit. On the other hand, the pHpzc value obtained for this system, happened to be unexpectedly high for Si02. These experiments ought to be treated cautiously, as the flat structure of the transistor surface differs much from the structure of the surface of dispersed particle. The next problem may be caused by possible contaminants and the surface property changes made by their presence. 

Three catalysts prepared in this study showed a relatively severe and fast deactivation than the commercial catalyst. To investigate the reasons of the catalyst deactivation, SEM and EPMA methods were used to characterize the surface property changes after the dechlorination reaction. SEM images of the catalyst before and after the dechlorination reaction at different temperatures are shown in Fig. S. Significant coke formation was observed only in the sample tested at 500°C. The coke was filamentous and its diameter was approximately 40nm. High reaction temperature of 500 C is considered to be the major reason of the coke formation. 

Carlson, J. D., Bares, J. E., Guzman, A. M., and Pronko, P. R, Surface property changes induced in poly(l-hexene) elastomer by high energy ion irradiation, Nucl. Instrum. Methods Phys. Res., B7/8, 507-512 (1985). 

The direct method is used to evaluate surface modification results by measuring surface property changes of whiskers before and after modification. 

Measuring Techniques and Surface Properties Changed by Adsorption... 

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