. Each experiment was initiated by pre-treating the catalyst sample in pure O2 flowing at 100 cm3/min for 2 h at 873K. The sample was then flushed in helium and cooled to the desired adsorption temperatures, 5
. Each experiment was initiated bypre-treating the catalyst sample in pure O2 flowing at 100 cm3/minfor 2 h at 873K. The sample was then flushed in helium and cooledto the desired adsorption temperatures, 5