Open and Closed Circuit Kinetics

A very pronounced, 10-fold, increase in catalytic rate is obtained for high P02/PH2 values (Fig. 9.28). The rate enhancement ratio po defined from  

More importantly, as shown in Fig. 9.28, increasing catalyst potential causes a pronounced increase in the po2 value, po2 which maximizes the 

These observations show that, as in NEMCA studies in solid state and aqueous electrochemistry, the observed pronounced catalytic rate modification is primarily due to the change in the binding strength of chemisorbed O and H with changing catalyst potential. 

The isomerization of 1-butene to cis- and trans- 2-butene onPd/C/Nafion and Pd-Ru/Nafion electrodes is one of the most remarkable and astonishing electrochemical promotion studies which has appeared in the literature.39,40 Smotkin and coworkers39,40 were investigating the electrocatalytic reduction of 1-butene to butane on high surface area Pd/C and Pd-Ru cathodes deposited on Nafion 117 when, to their great surprise, they observed at slightly negative overpotentials (Fig. 9.31) the massive production of 1-butene isomerization, rather than reduction, products, i.e. cis- and trans-2-butenes. This is extremely important as it shows that electrochemical promotion can be used also to enhance nonredox catalytic reactions such as isomerization processes. 

The electrochemical cell consists of high surface area Pd/C or unsupported Pd-Ru cathodes interfaced to Nafion with a Pt-black/H2 counter electrode. The cell configuration, as well as the reactions taking place on the anode and the cathode are the following  

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