Adsorption of methane as well as co-adsorption of methane and O on NirAl O catalyst have been studied by in situ 2 2 3 FT-IR spectroscopy. The reaction start temperature measurements indicate that the methane partial oxidation occurs at 2308C. As the reduced NirAl O was exposed to pure CH , two bands for adsorbed methane were observed at 3005 and 2 3 4 2998 cm y1 , respectively, which was confirmed by the appearance of two bands at 2242 and 2237 cm y1 when CD was 4 Ε½ . Ε½ . used. During temperature programmed TP dynamic process in the presence of CH , the intensities of the bands at 3005 4 and 2998 cm y1 increased with increase in temperature, indicating that the amount of adsorbed methane increases with Ε½ increasing temperature, which is indicative of chemisorption of methane. During TP dynamic process in the co-presence of . CH and O , two forms of chemisorbed methane are observed. The amount of chemisorbed methane increased with 4 2 increasing temperature. At 2508C, the intensity of the band at 3015 cm y1 for gaseous methane decreased remarkably and at the same time, CO, H , CO and H O were detected in the gas phase, indicating that the partial oxidation of CH occurs, 2 2 2 4
which is in good agreement with the reaction start temperature observed above. These results suggest that the dissociation of chemisorbed methane in the participation of chemisorbed oxygen is a key step for methane partial oxidation.