Ca. Cavalca et al., ELECTROCHEMICAL MODIFICATION OF CH3OH OXIDATION SELECTIVITY AND ACTIVITY ON A PT SINGLE-PELLET CATALYTIC REACTOR, Journal of physical chemistry, 97(23), 1993, pp. 6115-6119
It was found that the catalytic activity and selectivity of Pt for the
oxidation of methanol to formaldehyde and CO2 can be altered signific
antly and reversibly by depositing a Pt catalyst film on an yttria-sta
bilized zirconia (YSZ) disc and by applying current or potential betwe
en 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. Th
e observed increase in the rate of H2CO production was typically a fac
tor of 100 higher than the rate of O2- supply to the catalyst with a c
oncomitant 2-fold increase in selectivity. This demonstration of the e
ffect of non-Faradaic electrochemical modification of catalytic activi
ty (NEMCA) to reversibly modify catalyst activity and selectivity in a
single-pellet flow reactor is a new result. It has considerable pract
ical importance as it shows that the NEMCA effect can be utilized in c
onventional flow-type catalytic reactors. The present study has also s
hown the spontaneous generation of significant reaction-driven potenti
al differences between the catalyst and the counter electrode. This ob
servation is significant both for catalytic and also for sensor applic
ations.