A simple model catalyst study to distinguish the roles of different oxygen species in propane and soot combustion

It is important yet difficult to distinguish the specific roles of superficial O(x)(n- )and interfacial lattice oxygen in catalytic combustion, especially over catalysts consisting of reducible metal oxides. In this study, based on the comparison of two natural counterparts with similar structure - CeO2 (an Oxn-generator) and Pr6O11 (a lattice oxygen contributor), it is suggested that the catalytic combustion of propane under lean-burn conditions followed a typical Mars-van Krevelen mechanism, in which catalyst lattice oxygen represented the dominant reactive phases while superficial O(x)(n- )played negligible roles. As for soot combustion, adsorbed O-x(n-) represented more sustainable oxidants than lattice oxygen (drained easily at the beginning of the reactions). Such a comparison is readily achieved and widely applicable, which may shed light on the identification of dominant reactive phases for various oxidation reactions over oxide-based catalysts.