Reaction kinetics in porous electrocatalysts

Abstract

In a theoretical and experimental study of the effect of pore diffusion on the electrode kinetics of non-first-order reactions (e.g., hydrocarbon fuel cell reactions), a simple pore model was used successfully to describe the reaction in the pores of a partially wettable electrocatalyst. Experiments on the electrogenerative hydrogenation of gaseous olefins (ethylene through butylene) and of liquid benzene on polytetrafluoroethylene-bonded porous electrodes, activated with 9 mg/sq cm platinum or palladium black, were in good agreement with calculations by the model and showed that partially wettable porous catalytic electrodes behave kinetically similar to conventional catalysts when pore diffusion is slow. Kinetic studies on porous electrocatalysts can, therefore, be meaningful for catalyst characterization and for the design of electrochemical reactors.