Enhanced coke resistance of Fe-based garnets by in-situ formed CuFe alloy for chemical looping partial oxidation of methane

It remains a grand challenge to inhibit coke formation for Fe-based oxygen carriers with extensive reduction due to the mismatch between the CH 4 decomposition rate on metallic Fe (Fe 0 ) and the rate of the lattice oxygen migration to the surface for carbon oxidation, which led to unsatisfactory syngas selectivity and productivity for chemical looping partial oxidation of methane (CLPOM). Herein, Cu-modified Fe-based garnets (Y 3 Fe 3 Cu x Al 2− x O 12 abbreviated as Fe 3 Cu x Al 2− x , x equals 0, 0.01, and 0.05) were designed, which exhibited boosted carbon-resistance with both CH 4 conversion and CO selectivity of 94% and extraordinary syngas productivity of almost 8 mmol g −1 for Fe 3 Cu 0.05 Al 1.95 , surpassing most of the state-of-the-art Fe-based oxygen carriers in CLPOM. This could be attributed to the in-situ formation of a CuFe alloy under reaction conditions, which remarkably decreased the activity of CH 4 decomposition over Fe 0 sites to generate carbon and thus allowed lattice oxygen migration to the surface timely for the oxidation of coke formed.