(3y) Integrating Nanoscale Phenomena to Catalytic Applications Through Material Design

Advances in the synthesis of nanoscale materials have permitted more direct assignment of property changes that occur due to quantum and nanoscale size effects.  In particular, the size of nanoscale materials changes physical, chemical, optical, and catalytic properties.  Exploiting the novel properties of nanoscale materials for catalytic applications will reveal interesting properties that can be tuned in order to enhance catalytic performance.

My PhD research experience involved a plasma-based aerosol synthesis method for nanoparticles and characterization of nanomaterials.  The limited ability of current technology to determine nanoparticle size in situ led me to design, build, simulate and validate the nano-RDMA, a new instrument capable of classifying nanoparticle size in the one to ten nanometer size range.  The instrument performance permitted in situ investigation of size effects on surface dehydrogenation of silicon nanoparticles, demonstrating a lower activation barrier for dehydrogenation from small clusters.  Additionally, the capabilities of the instrument were tested through demonstrating the sputter production of atomic clusters (<1 nm in size) from an atmospheric plasma source. 

In addition to synthesizing and characterizing nanoparticles, my research involved designing, building, and characterizing an electrospray source that was used to incorporate platinum nanoparticles in membrane electrode assemblies (MEAs) for low catalyst loading, solid acid fuel cell applications.   The electrospray source produced crystallites of the fuel cell membrane material on the scale of 100 nanometers – smaller than ever produced before - while simultaneously mixing platinum nanoparticles to create the MEA.  The reduced size discrepancy between the catalyst particle (i.e. 10 nm) and the membrane material permitted low catalyst loading for the fuel cell.

My post-doctoral research examines the cooperativity between organic acid and base sites in bio-inspired cooperative catalysis.  Through designed immobilization of acid and base sites on a rigid support, the interaction of organic functional groups (that would otherwise quench each other) can be controlled, permitting the ability to design-in catalytic cooperativity at the nanoscale.  Alternatively, a more flexible support can be used, allowing an additional way whereby the acid-base interaction strength can be tuned. 

Integrating my background of instrumentation design, nanomaterials, and catalysis, my future research will exploit nanoscale design to control material functionality for applications in the fields of energy, catalysis, and advanced functional materials.  Characterizing surface and bulk properties will elucidate properties that develop due to the size of the materials, requiring new techniques and associated instrumentation to probe subtle yet significant changes that occur.  The integrated and multidisciplinary probing of materials properties will lead to fundamental discoveries of nanoscale material properties.

Post-doctoral Advisor: Christopher W. Jones, Georgia Institute of Technology, School of Chemical & Biomolecular Engineering

Doctoral Thesis Committee: Professors Konstantinos P. Giapis, Richard C. Flagan, Sossina M. Haile, J. L. Beauchamp, California Institute of Technology, Division of Chemistry and Chemical Engineering

Publications:

[1] N.A. Brunelli, R.C. Flagan, K.P. Giapis, Aero. Sci. Tech. 2009, 43, 53-59.

[2] A. Varga, N.A. Brunelli, M. Louie, K.P. Giapis, S.M. Haile, J. Mat. Chem. 2010, 20, 6309-6315.

[3] J. Jiang, M. Attoui, M. Heim, N.A. Brunelli, P. McMurry, G. Kasper, R.C. Flagan, K.P. Giapis, and G. Mouret, Aero. Sci. Tech. 2011, 45, 48-492.