(509n) Nanocomposite Materials For Clean Energy Applications

The large surface areas and reports of novel chemical reactivity make nanomaterials highly interesting for heterogeneous catalysis. The low stability of nanoparticles, however, typically restricts their use in reactive environments, in particular at high temperature conditions. We previously demonstrated the successful synthesis of unusually active and sinter-resistant nanocomposite materials which combine the high reactivity of nano-sized noble metal particles with the excellent high-temperature (~1000°C) stability of hexa-aluminates. In this contribution, we present a detailed structural characterization of these nanocomposites, which allows us to explain their unusual stability. Combining N2 porosimetry, high resolution TEM, XRD, and DTA in characterizing the hexa-aluminate pore structure and platinum particle size distributions, we can trace the stability of the noble metal nanoparticles back to a ?caging' effect by the hexa-aluminate matrix. In addition, we demonstrate the flexibility of these catalysts for a number of closely related clean energy applications: hydrogen and syngas production via catalytic partial oxidation of methane, catalytic combustion of methane, and chemical looping combustion of synthesis gas. We find strongly enhanced kinetics and excellent stability of these materials in all of the reaction systems, thus demonstrating their great potential in future energy technologies.