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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.
Wang et al. (Tue,) studied this question.