Composite catalytic materials for steam reforming of methane and oxygenates: Combinatorial synthesis, characterization and performance

Using robotic workstation, a number of composite materials based on NiO/yttria-doped zirconia (YSZ) cermet promoted with doped ceria-zirconia fluorite-like mixed oxides and Ru were synthesized. The materials were characterized by XRD, BET,TEM, H-2 TPR, and their catalytic performance was estimated in the reactions of methane, ethanol and acetone steam reforming at short (10-36 ms) contact times. The amount of deposited carbonaceous species was estimated by temperature-programmed oxidation. Complex fluorite-like oxides as promoters minimize coking even in stoichiometric fuel/steam feeds. Promotion by small (<1 wt.%) amount of Ru further decreases coking and facilitates activation of such molecules as CH4 and acetone, thus ensuring a high level of performance in the intermediate temperature (500-600 degrees C) range. Factors controlling performance of these composites in steam reforming reactions such as lattice oxygen mobility in complex oxide promoters controlled by their chemical composition, strong interaction between components in composites, state and reactivity of supported Ru were assessed. (C) 2008 Elsevier B.V. All rights reserved.