Mesoporous silica supported LaCoO3 perovskites as catalysts for methane oxidation

A series of mesoporous silica supported LaCoO3, perovskites with various La-Co oxide contents (from 10 to 50 wt.%) was synthesized by impregnation of a La-Co citrate complex with highly ordered mesoporous silica followed by calcination, The loaded catalysts were characterized by means of XRD, BET, TEM techniques and their catalytic activity was tested for complete methane oxidation. The results revealed that after calcination at 600 degreesC, highly dispersed LaCoO3 perovskite was formed within the pore channels of the mesoporous host. No La-oxide and Co-oxide phases were detected by XRD. The specific surface area, pore volume and pore diameter of the loaded samples gradually decreased with increasing LaCoO3 content. These catalysts displayed high specific surface area and good thermal stability. They showed catalytic activities and resistance to SO, poisoning in the complete methane oxidation higher than bulk LaCoO3 perovskites. However, an internal diffusion control was observed at high temperature (conversion >40%), as a result of the one dimensional mesopore channels of the supports. (C) 2002 Elsevier Science Inc. All rights reserved.