Catalytic flameless combustion of methane over perovskites prepared by flame-hydrolysis

A set of perovskite-type catalysts of general formula LaBO3+/-delta (B = Co , Mn, Fe) and a sample of La2NiO4+/-delta were prepared by means of a recen tly proposed innovative flame-hydrolysis procedure. The catalysts were char acterised by nanometer-size particles (20-60 nm), relatively high surface a rea (ca. 20 m(2)/g), high thermal stability and high phase purity. Their hi gh activity for the catalytic flameless combustion of methane confirmed the validity and versatility of the preparation method. Temperature-programmed -desorption and -reaction, coupled with mass spectro metric analysis, allowed to better understand some aspects of the catalytic behaviour shown by the present samples for the cited reaction. In particul ar, an interesting correlation between the availability of oxygen at variou s temperatures, as revealed by the so-called alpha and beta oxygen desorpti on peaks, and reaction mechanism was found for the different B metals. (C) 2001 Elsevier Science B.V. All rights reserved.