Enhanced Chemical looping oxidative coupling of methane by Na-doped LaMnO3 redox catalysts

Abstract Chemical looping oxidative coupling of methane (CLOCM) describes an energy-saving and redox approach to convert methane into C2 products, which utilizes lattice oxygen in redox catalysts in place of molecular oxygen, to facilitate the oxidative coupling of methane reaction. This study synthesized a series of alkali Na-doping LaMnO3 as the redox catalysts for chemical looping oxidative coupling of methane. Incorporation of Na into LaMnO3 lattice induced the higher molar ratio of Mn4+/Mn3+ and more oxygen vacancies, which would be correlated to defects inside the material lattice and consequently promote the redox performance of Mn-based oxygen carriers. Characterizations and consecutive pulse tests showed that the surface oxygen species would be the active center for the methane activation, while a kind of un-fully reduced lattice oxygen (Oα-, 0