Catalytic and electrocatalytic oxidation of ethanol over a La0.6Sr0.4Co0.8Fe0.2O3 perovskite-type catalyst

The catalytic and electrocatalytic behavior of the perovskite-type La0.6Sr0 .4Co0.8Fe0.2O3 catalyst was investigated during ethanol oxidation. Experime nts were carried out at atmospheric pressure in a fully yttria-stabilized z irconia (YSZ) continuously stirred tank reactor (CSTR) in the temperature r ange between 300 and 750 degreesC and fuel-rich reactant mixtures (P-O2 = 2 kPa, P-ethanol = 13.5 kPa). It was round that oxygen-nitrogen streams satu rated with ethanol (at room temperature and atmospheric pressure) lead main ly to the formation of formaldehyde and acetaldehyde. For the aforementione d reaction conditions, gas-phase oxidation becomes predominant at temperatu res higher than 650 degreesC and in combination with heterogeneous phenomen a leads to 100% ethanol conversion and high acetaldehyde yields (75%) at ab out 750 degreesC. The electrochemical supply of oxygen anions mainly affect s the formation rates of CO and CO,. Due to the high operating temperatures , direct electrocatalysis and homogeneous reactions, more than NEMCA (Lambd a (max) = 3), affect the overall kinetic behavior. (C) 2000 Elsevier Scienc e B.V. All rights reserved.