Unsupported systems

The (ice)-1/2 frequency dependence appears also in the impedance function of unsupported systems, that is, when the transport of the electroactive species proceeds via coupled diffusion and migration. 

In evaluating our results and conclusions in relation to the industrial catalyst(J ), an account should also be taken of the effect of the silica support, which has not been considered here and yet is likely to play a role. In fact, as shown previously( 7,1 ), the phase distribution of the (Te,Ce)0 system differs from that of the (Te,Ce)O/SiO2 system at the same activation temperature due to the dilution and interaction effect which affects the respective formation rates and stability ranges of the various phases. In fact, from x-ray diffraction data of a fresh SiO "supported active ternary phase, the formation of some Ce02 is inferred, contrary to the results of the unsupported system. For these reasons, additional spectroscopic and catalytic... 

Coupling of Electrode Kinetics and Space Charge Dynamics in Unsupported Systems, in Proc. Third Symposium on Electrode Processes, ed. S. Bruckenstein, J. D. McIntyre, B. Miller, and E. Yeager, the Electrochemical Society 1980 Proceedings 80-3, 94—114. 

The catalytic activity and selectivity of the TMS arises from the electronic and structural properties of the sulfides themselves. Support effects are secondary, improving sulfide dispersion and reducing metal cost in commercial catalysts. Fundamental effects can only be elucidated by studying TMS catalysts in their fully sulfided and catalytically stabilized states. Studies are often simplified by studying the unsupported TMS. The study of supported catalysts could also be useful if the experiments are carefully designed, and the results are compared consistently with those from unsupported systems. 

The systems represented by the classical Debye dispersion model at constant temperature exist as multicomponent systems. So-called "electrorheolog-ical fluids" (Section 12-3) represent examples of such a system. In many other "real-life" systems the Debye capacitive transition is often not observed due to the presence of measurable ionic conduction (= 1/Rjx-) parallel with high-frequency bulk capacitance and resulting "lossy relaxation" with time constant T = Even in highly resistive "unsupported" systems there is... 

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