Contribution of Different Species in Ni‐Ceria Nanorods Catalysts Applied to Steam Reforming of Ethanol

Ni‐CeO2 nanorods catalysts (1–10 wt% Ni loadings) were evaluated in steam reforming of ethanol (SRE). Ex situ and in situ characterization showed two populations of Ni species according to Ni loading: (i) one highly dispersed, strongly interacting with CeO2 (Nisup) and (ii) another one formed by Ni nanoparticles (Nibulk). While the metal loading impacted on the Nibulk fraction, the Nisup population remained similar, leading to similar activities of the catalysts toward SRE. The results highlight the role of the Nisup fraction in the catalyst performance. Nevertheless, we found that while Nibulk species favored carbon deposition, the Nisup species were easily oxidized at low temperatures, leading to catalyst deactivation. The results suggest that the co‐existence of both Ni species may stabilize the reduced form of the Nisup species by hydrogen activation on the Nibulk species and represents a new strategy to be explored to optimize the activity and stability of SRE catalysts. Nickel loading effect on steam reforming of ethanol: Two populations of Ni species on ceria nanorods were observed. The smaller ones (Nisup, observed in all catalysts) were the most active, but quickly deactivated by oxidation at low temperature. Ni nanoparticles (Nibulk, observed at higher loadings) helped to stabilize the Nisup fraction reduced, leading to a more stable catalyst.