Catalytic activity of powder and monolith perovskites in methane combustion

Honeycomb monolith perovskite catalysts were prepared from ultradispersed powders of mixed oxides of rare-earth metals (La-Ce or Dy-Y) and transition metals (Ni, Fe, Mn) by mechanochemical methods. A plasmochemical method was used to obtain La-Ni containing monoliths. The catalytic activity of powders and monoliths was compared in the catalytic combustion of methane. The intrinsic catalytic properties of the active components (apparent kinetic constant and energy of activation) were not significantly affected by the manufacturing procedure of monoliths in a large range of temperatures. Best performance was exhibited by La-Ni oxides containing monoliths which possess the highest pore volume and fraction of macropores. (C) 1999 Elsevier Science B.V. All rights reserved.