Effect of preparation method on activity and stability of LaMnO and LaCoO catalysts for the flameless combustion of methane

Abstract

A set of LaMnO3 and LaCoO3 catalysts was prepared through different synthesis procedures. The selected techniques included the sol-gel method, flame hydrolysis from aqueous solution, complexation through EDTA and solid-state reaction. The last was accomplished through reactive grinding by ball milling either in a vibration mill or in a planetary mill. EDTA complexation was applied for LaCoO3 only and did not improve significantly catalyst activity or stability, with respect to other techniques. Ball milling never allowed obtaining a pure perovskitic phase, at least under the most energetic grinding conditions permitted by our apparatus. The highest activity for the catalytic flameless combustion of methane was obtained with the sol-gel prepared samples, though thermal resistance revealed insufficient for high temperature applications. A bit lower activity, but coupled with good thermal stability was obtained with the samples prepared through flame hydrolysis.

Effect of Preparation Method and Calcination Temperature on LaCoO3 Perovskite Catalyst for Diesel Soot Oxidation

“…It can be seen from the table that the various perovskite have low specific surface area (7-15m 2 /g) and Average pore size (13)(14)(15)(16)(17)(18)(19)(20) Å), which is in expected range considering the high synthesis temperature in accordance with references [32,33]. The catalysts formed at 600 o C showed the highest surface area irrespective of the preparation methods.…”

“…There have been studies reported on CO oxidation and other automotive pollutants [31][32][33] removal over LaCoO 3 catalysts prepared by specific single method and calcination temperature. However no work has been reported to examine the effects of various preparation methods and calcination temperature on the performance of LaCoO 3 catalysts for diesel soot oxidation.…”

Synthesis and Performance of Transition Metal Based Perovskite Catalysts for Diesel Soot Oxidation

“…It can be seen from the table that the various perovskite have low specific surface area (4-9 m 2 /g) and average pore diameter (36-42 Å), which is in expected range considering the high synthesis temperature in accordance with references [9,10]. The LaCoO3 sample, calcined at 750 o C in stagnant air, showed the highest surface area (09.12 m 2 /g).…”

NO oxidation over Ni–Co perovskite catalysts

“…For all samples, there were two main desorption peaks in the whole temperature range: one was at low temperature (<300°C) and the other was at high temperature (>300°C). The NO desorbed from the catalysts below 300°C was ascribed to NO adsorbed at B site in perovskite structure while the NO desorbed above 300°C was mainly from the decomposition of metal nitro or nitrate on the perovskite surface [21,22]. Compared with LaCoO 3 , LaNiO 3 exhibited lower amount of adsorbed NO and larger distance between two desorption peaks, which indicated that the B site was relevant to NO adsorption [21].…”