Oxygen step-response experiments for methane oxidation over Pd/Al2O3: An in situ XAFS study

Methane oxidation over Pd/Al2O3 has been investigated by in situ XAFS characterization during oxygen step-response experiments. With a net-reducing feed gas, Pd is in a reduced state and the introduction of oxygen leads to oxidation of palladium as well as increased methane conversion. When the rate of Pd oxidation is slow, a transient surface oxidized state is observed with low activity for methane oxidation. The activity increases when palladium is further oxidized and the highest activity is observed for palladium oxide.