How does Pr enhance metal-support interaction in Ni-containing LaCePr(n)Ox solid solution for dry reforming of methane?

Ni/LaCePr(n)Ox and Ni-LaCePr(n)Ox catalysts (1–10 mol% Pr) are prepared by incipient wetness impregnation of La(1-y)/2Ce(1-y)/2PryOx solid solutions and by one-pot synthesis. The one-pot-derived Pr-modified catalysts exhibit more homogeneous distribution of the active component and smaller Ni nanoparticles compared with the impregnated samples, which results in suppression of carbon deposition by one order of magnitude compared to the unmodified catalysts. The enhanced stability of the Pr-modified catalysts is attributed to an enhanced metal-support interaction between Ni0 nanoparticles and LaCePr(n)Ox solid solution, with 5 mol% Pr providing the optimal balance between initial activity and long-term stability for both catalyst series. Based on our findings and literature analysis, we propose a model describing possible processes at the metal-support interfaces that lead to Ni redispersion and dynamic balance between carbon formation on Ni nanoparticles and the oxidation/gasification of carbon species at the Ni-LaCePr(n)Ox interface.