Kinetic assessment of dry reforming of methane on Pt plus Ni containing composite of fluorite-like structure

Methane dry reforming kinetics over the 1.2% Pt/80% Pr0.15Sm0.15Ce0.35Zr0.35Ox + 10%NiO + 10% YSZ catalyst (Pt + Ni/PrSmCeZrO/YSZ) has been assessed. First-order kinetics in methane was found for the forward reaction rate up to an equimolar methane/carbon dioxide feed ratio. The reaction rate was inhibited by adding methane beyond the stoichiometric value. A relatively constant zero reaction order towards CO2 can be applied when a CO2 excess of at least 1.5 over the stoichiometric value is employed. The existence of two different activation regimes is evident in Arrhenius plots with an inflection point at about 750 degrees C. Kinetic parameters for the net rate of CH4 conversion over the Pt+Ni/PrSmCeZrO/YSZ composite catalyst were also determined by regression. The novel Pt+Ni/PrSmCeZrO/YSZ catalyst was benchmarked against a complex Pt-promoted fluorite-like doped ceria-zirconia oxide sample of similar atomic fractions of the corresponding elements (Pt/PrSmCeZrO/YSZ) in methane dry reforming. The Pt+Ni/SmPrCeZr/YSZ nanocomposite catalyst is regarded to be the most effective on a per unit mass basis. Higher methane conversions and H-2/CO ratios in the synthesis gas were obtained, while only minor differences were observed in the CO2 conversions. (C) 2015 Elsevier B.V. All rights reserved.