Catalytic evaluation of perovskite-type oxide LaNi1−xRuxO3 in methane dry reforming

The methane reforming with carbon dioxide (dry reforming) has been proposed as one of the most promising technologies for producing hydrogen by the use of two greenhouse gases. However, undesirable coke formation is the crucial issue to develop efficient catalysts for the reaction. In order to find alternative catalysts, which can be more resistant against coke deactivation, perovskite-type oxides LaRuxNi1−xO3 (0.0 < x < 1.0) were studied in this work. Samples were prepared by thermal decomposition of amorphous citrate precursors followed by heating at 800 or 1000 °C, for 12 h, in air. The solids were characterized by X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption, specific surface area measurements and X-ray photoelectron spectroscopy. The catalysts were reduced under hydrogen and tested in methane dry reforming at 1 atm and 750 °C. The coke produced was characterized by thermogravimetry, carbon measurement and scanning and transmission electron microscopy. The oxide precursors showed low specific surface areas and different reducing behavior. All catalysts were active in the reaction. They all produced filamentous coke but it was not harmful to the catalysts. Nickel is more active and selective to hydrogen than ruthenium but the later improved the stability of the catalysts decreasing coke formation. The most promising catalyst was the LaNi0.8Ru0.2O3 sample, which was the most resistant against coke deposition.