Abstract
Three noble metal catalysts (Rh-, Pt-, Ru/Ce0.75Zr0.25O2-delta) for reforming of hydrocarbons were studied in steam and autothermal process conditions. Each catalyst was prepared by sorption-hydrolytic deposition with a metal loading of 0.1 mmol/g. The main idea of this technical approach was to form a solution of "metal complex + alkaline agent" that was metastable at given conditions (temperature, concentrations) with respect to homogeneous metal hydroxide precipitation, due to the kinetic inertness of the metal complexes for ligand exchange. As the support surface accelerated heterogeneous nucleation and growth of metal hydroxide particles, addition of the support to the reagent mixture initiated the hydrolysis which led to uniform depositing of 1-2 nm metal particles over the support surface. The Rh-based catalyst synthesized surpassed the Ru- and Pt-based catalysts in activity and stability in that under the experimental conditions, complete n-hexadecane conversion and equilibrium reformate product distribution were observed for 1-wt. % Rh/Ce0.75Zr0.25O2-delta for 17 h. This catalyst also showed competitive performance in autothermal reforming of diesel fuel providing stable operation for 9 h.