Highly Active and Anticoke Ni/CeO₂ with Ultralow Ni Loading in Chemical Looping Dry Reforming via the Strong Metal–Support Interaction

Oxygen carriers with active sites have attained wide attention for chemical looping reforming of CH 4 recently thanks to their capacity to improve CH 4 activation and oxygen reactivity. However, supported metals sintered significantly during multiple cycles, which entailed high metal loading (generally >5 wt %) to realize great performance promotion and caused coke formation. Herein, merely 0.1 wt % Ni addition into CeO 2 could achieve remarkable enhancement of performance for chemical looping drying reforming of methane with CH 4 conversion and CO selectivity of almost 100% as well as syngas productivity of 3.4 mmol/g without carbon deposition. This resulted from the encapsulation of Ni nanoparticles by CeO 2 via the strong metal–support interaction during redox cycles preventing Ni nanoparticles from sintering, which brought about more surface oxygen vacancy for CH 4 activation compared with CeO 2 . Nonetheless, the covering could not be observed in 5Ni/CeO 2 resulting in the evident growth of Ni nanoparticles, which induced CH 4 cracking on them and thus coke formation.