(92a) Mixed Oxide Particles As Oxygen Separation Agents for Methane Partial Oxidation and Water/Carbon Dioxide Splitting

The current study presents mixed metal oxide particles as effective oxygen separation/carrying agents for methane partial oxidation and carbon dioxide or water reduction. In the proposed process, active lattice oxygen in a mixed oxide redox catalyst, a.k.a. oxygen carrier, is first used to partially oxidize methane into syngas, the oxygen-lean redox catalyst is subsequently regenerated with water to produce hydrogen. Alternatively, CO₂ can be used for redox catalyst regneration, producing CO. We will report a rationalized approach to optimize mixed oxide based redox catalyst for the aforementioned redox reactions.

Extensive characterizations in a thermogravimatric analyzer (TGA), an integral bed reactor, and a fluidized bed indicate that the redox catalyst is capable of achieving over 95% syngas selectivity in the methane partial oxidation step. The reduced redox catalyst is shown to be capable of converting CO₂ into a near pure CO stream. Steam to hydrogen conversion of nearly 100% was also observed. The exceptional syngas selectivity and CO₂ conversion are attributed to a combination of the satisfactory thermodynamic properties of the redox catalyst and enhanced redox kinetics through support and oxygen carrier interactions. Strategies for surface promotion of the redox catalyst for "low-temperature" operations are also discussed.