COMPARISON OF LANTHANUM OXIDE AND STRONTIUM-MODIFIED LANTHANUM OXIDE CATALYSTS FOR THE OXIDATIVE COUPLING OF METHANE

The activity and selectivity of lanthanum oxide and strontium-modified lanthanum oxide catalysts for the oxidative coupling of methane have been compared. Lanthanum oxide is more active than strontium-modified lanthanum oxide. This is thought to be due to a reduction in the surface concentration of active lanthanum, by replacement with less active strontium carbonate. During methane coupling, catalyst performance varies. This is dependent on calcination temperature and the presence of strontium carbonate. These variations are related to the relative concentration of two types of lanthanum oxycarbonate which may be formed, and their stability, during reaction.