Low Temperature Partial Oxidation of Methane over Bimetallic Nickel-f Block Element Oxide Nanocatalysts

The partial oxidation of methane (POM) was studied over bimetallic nickel-f block element oxide nanocatalysts prepared by a modified sol-gel method. They proved to be active (conversion of methane, 50-70%) at a relatively low temperatures (550 and 650 degrees C) and highly selective towards synthesis gas production (selectivity, H-2 60-90% and CO 50-80%). The activity and selectivity depend on the surface basicity and size of the bimetallic oxide nanoparticles: lower particle size and higher basicity, enhanced activity and selectivity to synthesis gas. Catalysts reducibility seems as well to promote their activity and selectivity. The bimetallic nickel-gadolinium and nickel-thorium oxide nanocatalysts proved to be more active and selective towards synthesis gas production than a commercial platinum supported catalyst (5 wt% Pt/Al2O3) or other bimetallic nickel oxide catalysts obtained by a different high temperature preparation route, which stresses the advantage of the preparation method. The bimetallic nickel-f block element oxide nanocatalysts present also remarkable long-term stability and an unusual low deposition of carbon, which is a major advantage, especially when compared to other nickel-based catalysts reported for POM. Such a behavior was attributed to the lanthanide or actinide oxide phases that appear to play an important role on the catalysts stability.