T. Norby et al., OXIDATION OF METHANE ON A AU-DELTA(SRFEO3)/YSZ ELECTRODE CHARACTERIZED BY MASS-SPECTROSCOPY AND 18O2 PULSES/, Chemical engineering & technology, 18(2), 1995, pp. 139-147
A solid state electrochemical reactor is described in which reactants
can be oxidised at high temperatures over an anode/catalyst using co-f
ed oxygen gas as well as electrochemically supplied oxygen. The setup
permits injection of isotopic pulses in the reactant streams. The comp
osition and isotopic distribution in the products are recorded with a
quadrupole mass spectrometer. The use of the system is exemplified by
oxidation of methane over a Au + SrFeO3 - delta//YSZ anode at 800 - 85
0-degrees-C. Pulses of O-18(2) in the stream of co-fed O2 were used to
study the reactivity and products of gaseous oxygen as distinguished
from the electrochemically supplied oxygen. The results indicate that
the anode used supports oxygen pumping, but is only moderately active
for methane oxidation. The products are mainly CO and CO2. The content
of O-18 in the products is low, indicating that methane oxidation tak
es place by O-16-rich lattice oxygen. In comparison, a reference Au//Y
SZ electrode was found to be a slower anode for oxygen pumping, but a
better catalyst for the reaction between CH4 and gaseous O2, seemingly
involving adsorbed oxygen.