The role of the distribution of Ce species on MoO3/CeO2–Al2O3 catalysts in sulfur-resistant methanation

CeO2–Al2O3 supports were prepared by different methods and applied as MoO3/CeO2–Al2O3 catalysts for sulfur-resistant methanation. All characterization analyses of the catalysts indicated that when the Ce species are distributed in the bulk of the catalysts, they are favorable for the stability of the catalyst whereas when the Ce species are distributed on the surface of the catalyst, they are beneficial for the initial activity. Stepwise sulfidation is applied on MoO3/CeO2–Al2O3 catalyst to eliminate surface Ce species and migrate them to the inside of the catalyst, this also demonstrates that the Ce species distributed in the bulk of the catalysts are favorable for the stability.

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► Two kinds of CeO2–Al2O3 with different distributions of Ce species were used.
► The catalyst is more stable when the Ce species are distributed inside the catalysts.
► The catalyst exhibits a higher activity when the Ce species are distributed on the surface.
► Stepwise sulfidation is applied to eliminate CeO2 on the surface of the catalyst.
► The catalyst sulfided by stepwise sulfidation is more stable.