An oxygen carrier catalyst toward efficient chemical looping-oxidative coupling of methane

Chemical looping concept paves way toward intrinsically safe and efficient oxidative coupling of methane (CL-OCM) process, because it permits the reaction to proceed via repeating reduction-oxidation cycle in two reactors. It is calling for a ground-breaking catalyst with enough high selective CH 4 -converting lattice-oxygen carrying capacity but represents a grand challenge. Herein, we report an efficient catalyst obtainable by decorating an oxygen carrier FeMnO 3 with Na 2 WO 4 , with good cycling performance, achieving a high space time yield of 29.8 g C2-C3 kg cat. −1 h −1 with 20% CH 4 conversion and 80% C 2 -C 3 selectivity at 800 °C and a low catalyst/CH 4 weight ratio of 13.5. CL-OCM process is established by “FeMnO 3 ↔ [MnFe 2 O 4 + MnO]” redox cycle. Na 2 WO 4 -decoration gets lattice oxygen stored in FeMnO 3 transformed from non-selective to selective due to mitigation of lattice-oxygen evolution. Scaled up CL-OCM testing with 10-gram catalyst also yields comparable results seen in the case of using 1-gram catalyst, validating great application potential.