Ni-containing Pr-Doped Ceria–Zirconia One-Pot Catalysts for Dry Reforming of Methane

<jats:p>A series of one-pot 5%Ni-CexPryZrzO2 catalysts was prepared using continuous flow synthesis in supercritical isopropanol. All samples are consisted of fluorite and NiO phases. According to HRTEM data, the samples morphology changes with increasing praseodymium content: particles become less spherical and plate-like particles appear. Raman analysis demonstrated a positive correlation between Pr content and the concentration of defects in the fluorite lattice. XPS analysis revealed that the surface of all samples is enriched with Pr compared to the stoichiometric composition. Increased Pr content also results in a greater depth of samples reduction and lower reduction onset temperature. 5%Ni-Ce0.65Pr0.3Zr0.05O2 had the highest activity in methane dry reforming and provided methane conversion of 53% at 700 °C, while the zirconium-free 5%Ni-Ce0.75Pr0.25O2 sample showed the lowest activity and provided methane conversion of 40%. With the exception of the zirconium-free sample, the catalytic activity follows a volcano-shaped trend as a function of praseodymium content.</jats:p>