Effect of Reactant Gas Composition and Utilization

The voltage of MCFCs varies with the composition of the reactant gases. The effect of reactant gas partial pressure, however, is somewhat difficult to analyze. One reason involves the water gas shift reaction at the anode due to the presence of CO. The other reason is related to the consumption of both CO2 and O2 at the cathode. Data (55,64,65,66) show that increasing the reactant gas utilization generally decreases cell performance. 

Due to the thickness range, L 10 — 20pm, the operation of conventional catalyst layers depends decisively on the availability of sufficient gas porosity for the transport of reactants. The pertinent theory of gas diffusion electrodes dates back to the 1950s with major contributions by A.N. Frumkin and O.S. Ksenzhek [79-81]. Specifically, catalyst utilization and specific effective surface area in composite electrodes were always the focus of attention (see, e.g. [82,83] and the articles quoted therein). 

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