Hydrogen production by methane tri-reforming process over Ni–ceria catalysts: Effect of La-doping

The objective of the present work is the study of CH4 tri-reforming process (simultaneous carbon dioxide reforming, steam reforming and oxygen reforming) that can contribute to the CO2 abatement producing synthesis gas with the desiderate H2/CO ratio.A series of Ni–CeO2 catalysts with different La loadings is prepared by combustion synthesis and tested as catalysts in CH4 Tri-reforming reaction at 800 °C under atmospheric pressure with a GHSV of 30,000 h−1.It has been found that during tri-reforming reaction the activity of Ni–ceria catalysts can be enhanced by an appropriate amount of La doping (10 at.%), the CH4 and CO2 conversion increases from 93% and 83% to 96% and 86.5%, respectively. The activity enhancement appears to be related to synergic effect of nickel–lanthana–surface oxygen vacancies of ceria via interfacial active sites that contribute to increase the nickel dispersion and create a basic site distribution on the surface able to interact with CO2.

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► Synthesis gas production by CH4-tri-reforming with Ni–CeO2 catalysts doped with La (x = 0.05–0.50).
► Partial formation of solid solution with negative (x = 0) and positive expansion (0.05 < x < 0.50) of the ceria lattice emerges.
► Superior performance of Ni–La–CeO2 (x = 0.10) sample were related to a synergic effect of nickel–lanthana–surface oxygen vacancies, nickel dispersion and basic sites distribution on the surface.