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.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry