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

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-CeOx bifunctional catalysts with different proximity and explore the influence of proximity level on anticoking performance. Ni-CeOx bimetallic nanoparticles with intimate contact are precisely regulated through the anchoring strategy of coordination unsaturated Al3+penta, which undergoes the topotactic exsolution of a Ni–Ce–O quasi-solid solution into Ni-CeOx bimetallic nanoparticles. A trend toward easier elimination and even the absence of graphitic carbon is observed with a decreasing spatial distance between Ni and CeOx, which is attributed to the proximity between the dissociation and gasification sites of CHx* intermediates. CHx* species generated at Ni nanoparticles migrated to adjacent CeOx oxygen carriers for Ni-CeOx/Al2O3 catalyst gasification with Ni-CeOx bimetallic nanoparticle interfaces, which undergo the Mars–van Krevelen (MvK) mechanism. The exploration of the Ni-CeOx proximity provides guidance for developing efficient and durable Ni-based DRM catalysts.