ELECTROCHEMICAL MODIFICATION OF CH3OH OXIDATION SELECTIVITY AND ACTIVITY ON A PT SINGLE-PELLET CATALYTIC REACTOR

It was found that the catalytic activity and selectivity of Pt for the oxidation of methanol to formaldehyde and CO2 can be altered significantly and reversibly by depositing a Pt catalyst film on an yttria-stabilized zirconia (YSZ) disc and by applying current or potential between the catalyst film and a Ag film deposited on the other side of the O2--conducting YSZ disc. Both the catalyst film and the Ag counter and reference electrodes are exposed to the reacting CH3OH-O2 mixture. The observed increase in the rate of H2CO production was typically a factor of 100 higher than the rate of O2- supply to the catalyst with a concomitant 2-fold increase in selectivity. This demonstration of the effect of non-Faradaic electrochemical modification of catalytic activity (NEMCA) to reversibly modify catalyst activity and selectivity in a single-pellet flow reactor is a new result. It has considerable practical importance as it shows that the NEMCA effect can be utilized in conventional flow-type catalytic reactors. The present study has also shown the spontaneous generation of significant reaction-driven potential differences between the catalyst and the counter electrode. This observation is significant both for catalytic and also for sensor applications.