Constructing Ni/Ln-CeO2 (Ln=La, Pr, Sm, Y) catalysts for low-temperature methane steam reforming (MSR): The remarkable enhancement effect of CeO2 lattice doping

Abstract

Environmental pollution caused by fossil energy is becoming more and more stringent, and the utilization of clean energy such as H₂ has attracted more attention. MSR is the main way of industrial hydrogen production at present, and developing more efficient catalysts is still desirable and one of the hot issues. In this study, Ni loaded on CeO₂-based solid solution supports doped by various rare earth ions (Ln = La, Pr, Sm, Y) in the matrix have been fabricated for the reaction. The reaction results have demonstrated that the catalytic performance and anti-coking ability follow the order of Ni/La₁Ce₁₉ > Ni/Pr₁Ce₁₉ > Ni/Sm₁Ce₁₉ > Ni/CeO₂ > Ni/Y₁Ce₁₉. Except for Ni/Y₁Ce₁₉, the number of surface oxygen vacancies, active oxygen, basic sites and Ni active surface of the doped catalysts is improved in comparison with the unmodified Ni/CeO₂. The synergistic interaction of the active oxygen anions, basic sites and the Ni active surface is the intrinsic reason to control the catalytic performance. Ni/La₁Ce₁₉ owns the richest amount of both kinds of active sites and the biggest Ni surface area, thereby exhibiting the best activity, stability, coking resistance and the highest H₂ production rate.