Thermal coarsening of supported palladium combustion catalysts

摘要: An essential property of combustion catalysts is long-term (>8000 h) stability at high temperatures in an environment (approximately 1 atm both oxygen and water vapor) that aggressively promotes sintering the supporting oxide coarsening active component. Extrapolation accelerated rate measurements, determined from shorter exposures higher temperatures, can be made with more confidence if physical processes were well understood. The current work examines detail a high-weight-loaded palladium catalyst supported by silica-stabilized alumina 900 degrees C such aggressive environment. results this investigation showed Pd particle size distribution was consistently log-normal for time periods 100 to 4000 h, mean growth roughly inverse second-order diameter, support not only sintered but also underwent phase transformation. implicate coalescence Ostwald ripening as important processes.