Journal of Catalysis, Vol.166, No.2, 324-332, 1997
Reaction-Kinetics of Methane Oxidation over Lacr1-Xnixo3 Perovskite Catalysts
Ternary perovskite oxides LaCr1-xNixO3, (x = 0 to 1.0) were evaluated as methane oxidation catalysts over the temperature range 300-500 degrees C and as a function of the partial pressures of oxygen and methane (12-90 kPa). All catalysts are stable in oxygen containing atmospheres, while oxygen starvation causes destructive reduction to Ni metal for x > 0.5. The catalytic activity increases monotonically with the value of x. The nonseparable (composition, temperature) kinetics behavior is well correlated by an oxidation-reduction mechanism for all catalysts. Based on the observed nonlinear increase in catalytic activity with nickel content, Ni-O-Ni ensembles are proposed as the key surface reagent.
Keywords:TEMPERATURE-PROGRAMMED TECHNIQUES;A-SITE CATION;CARBON-MONOXIDE;AUTO EXHAUST;OXIDES;COMBUSTION;REDUCTION;CONDUCTIVITY;LANIO3;METAL