Stabilizing Ni-CeO_<i>x</i> Bifunctional Nanoparticles on Activated Alumina to Enhance Carbon Resistance for Dry Reforming of Methane

Abstract

Syngas, an extremely meaningful chemical feedstock consisting of hydrogen and carbon monoxide, can be produced through methane dry reforming with carbon dioxide. The extensively utilized Ni-based catalysts usually suffer from coke-induced instability. Herein, we design Ni-CeO x bifunctional catalysts with different proximity and explore the influence of proximity level on anticoking performance. Ni-CeO x bimetallic nanoparticles with intimate contact are precisely regulated through the anchoring strategy of coordination unsaturated Al 3+ penta, which undergoes the topotactic exsolution of a Ni–Ce–O quasi-solid solution into Ni-CeO x bimetallic nanoparticles. A trend toward easier elimination and even the absence of graphitic carbon is observed with a decreasing spatial distance between Ni and CeO x, which is attributed to the proximity between the dissociation and gasification sites of CH x * intermediates. CH x * species generated at Ni nanoparticles migrated to adjacent CeO x oxygen carriers for Ni-CeO x /Al 2 O 3 catalyst gasification with Ni-CeO x bimetallic nanoparticle interfaces, which undergo the Mars–van Krevelen (MvK) mechanism. The exploration of the Ni-CeO x proximity provides guidance for developing efficient and durable Ni-based DRM catalysts.