Supercritically Functionalized Nanostructures for Methane Reforming

Natural gas, coalbed methane, and methane hydrates can be utilized in the methane conversion technology or fuel reforming. However, the process of internal fuel reforming has limitations in terms of carbon deposition, sulfur poisoning, and materials sintering. These limitations delay application of internal reforming processes in sustainable energy economy.

Fig.1: Major catalytic processes taking place during the internal reforming of methane.

R-FuelCellsFigure2   R-FuelCellsFigure3
Fig. 2: SOFC testing setup at South Dakota Mines   Fig. 3: Comparison of the state-of-the-art microstructure (a) with proposed ceramic nanostructure developed in supercritical fluid (b).

To overcome limitations, supercritical design and fundamental study of novel hybrid nanocomposites in terms of methane reforming kinetics and ability to eliminate carbon deposition are performed. The novelty of the approach is in understanding a correlation between the morphological properties of supercritically functionalized ceramic materials and their electrocatalytic properties in the process of internal methane reforming.

Advantages of materials design in supercritical environment is in absence of mass transport limitations for the organometallic precursors and thus, formation of self-assembled high surface area metal or metal oxide nanoparticles with advanced catalytic properties. Organometallic precursors form catalytically active and chemically stable architectures with an advantage of minimized grain boundary effect and point defect clustering providing homogeneous reduction and oxygen diffusivity. Fundamental study of the novel architectures will be focused on chemical interactions, morphology, electrical conductivity in reducing atmosphere, and electrochemical kinetics providing a valuable insight into the properties of supercritically synthesized nanostructured materials.

Scientific impact of the proposed research is in providing a fundamental understanding of correlations between the properties of the nanomaterials synthesized in supercritical fluids and their kinetic behavior at elevated temperatures. To the best of our knowledge, these materials have not been synthesized previously in supercritical fluid environment. This work will have significant impact on the novel materials design and provide us with new concepts in terms of materials development in supercritical environment that is important for electronics, energy generation devices, and medical applications.  Ceramic film deposition is controlled by precursor mass transport and solubility with respect to the density of scCO2 and the mass of the precursor.

The concepts developed in this project are incorporated into a new course “Materials for sustainable energy” and the outreach program for Native Americans it the State of South Dakota.