Michal Lutecki

Nickel-Loaded Zirconia Catalysts with Large Specific Surface Area for High-Temperature Catalytic Applications

Highly porous and thermally stable zirconia is prepared by a template‐assisted route using dodecylamine (DDA) and a post‐treatment in ammonia solution at different pH. The resulting materials are calcined at 700 °C and characterized by elemental analysis, optical emission spectrometry with inductively coupled plasma (ICP‐OES), N2 sorption, XRD, high‐resolution TEM, and, after loading with 5 wt % nickel, also by temperature‐programmed reduction and temperature‐programmed desorption of ammonia (TPDA). With increasing pH of the post‐treatment, the specific surface area increases up to 156 m2 g−1 and the diameter of the predominantly tetragonal crystallites decreases from 10.3 to 5.7 nm, independently of the presence of Ni. The high specific surface area is shown to be a result of the incorporation of silicon (<2.5 wt %) dissolved from the glass vessels during the post‐treatment. Despite the presence of acid sites, the Ni‐loaded zirconia are active and selective catalysts in the dry reforming of CH4 with CO2 at 750 °C. With conversions up to 79 % and H2 selectivities up to 87 %, the catalysts supported on zirconia prepared by the DDA route and ammonia post‐treatment are significantly more active than those with zirconia supports prepared by conventional precipitation or in the absence of silicon or DDA.

Diffusion and Reaction in Hierarchical Structured Metal Oxides – A Transient TAP Study

Transient TAP measurements have been performed for the first time on nanostructured hierarchical sulfated zirconias prepared by a template-assisted route. The newly designed catalytic materials showed different catalytic activities in the n-butane isomerization. The tailored pore systems had a significant influence on the diffusion properties of reactant and product molecules thus influencing the microkinetics.