Ni incorporation in Y-Fe-Al garnet oxygen carriers for enhanced chemical looping reforming of methane

Chemical looping reforming of methane (CLRM) is a promising technology for syngas production, offering efficient utilization of CH 4 to generate syngas with a desirable H 2 /CO ratio for downstream applications. This study investigated the influence of Ni incorporation in Y-Fe-Al garnet-type oxygen carriers (OCs) in CLRM. The Ni 0.2 -Y-Fe-Al OC demonstrated a pronounced enhancement in performance compared to its undoped counterpart, elevating the methane conversion from 66.6 % to 98.4 % and increasing the syngas yield from 5.79 to 8.38 mmol g −1 at 850 °C. The incorporated Ni species introduced additional active sites for methane activation, enhanced surface basicity, and improved lattice oxygen mobility, which collectively facilitated the selective oxidation of methane to syngas, especially at low temperatures (<850 °C). Cyclic tests confirmed that Ni incorporation enhanced the redox stability and mitigated phase segregation, leading to sustained high reactivity over multiple cycles. In situ DRIFTS analysis verified that the fundamental reaction pathway, proceeding via the -CH 3 →-CH 2 →-CHO intermediates, remained unaltered after Ni addition. This work established that incorporating Ni in garnet-type OCs is an effective strategy for enhancing both redox activity and cyclic stability in CLRM systems.