Alkaline-Earth Promoted SrTiO3 and Sr2TiO4 in Oxidative Methane Coupling: Role of Microstructure and Surface Composition on Activity, Kinetics and Oxygen Exchange
Доклады на конференциях
The aim of this work was to take a close look in catalytic performance of alkaline-earth promoted strontium titanates, being the active catalysts of oxidative methane coupling reaction (OCM), and to find the correspondence between the microstructure, catalytic activity, kinetics of OCM and oxygen exchange properties. We have found that under OCM conditions surface composition and microstructure of alkaline-earth promoted SrTi0.9A0.1O3 and Sr2Ti0.9A0.1O4 (A = Mg, Ca, Ba) may undergone a change revealing (Sr,A)O mixed oxide on the surface of the particles, which strongly increases both catalytic properties of titanates and the rate of the oxygen exchange between surface and bulk. Detailed kinetic analysis, together with electron microscopy, XPS, XRD and IR methods, allowed us to establish the quantitative relationships between the rate of methane conversion, selectivity, oxygen exchange characteristics and surface concentration of (Sr,A)O mixed oxide.