Hierarchical Materials Architectures for Enzymatic Fuel Cells

HIERARCHICAL MATERIALS ARCHITECTURES FOR ENZYMATIC FUEL CELLS 

Oak Ridge Institute of Science and Engineering, Oak Ridge, TN, USA Airbase Sciences Branch, Air Force Research Laboratory, Tyndall Air Force Base, FL, USA 

Airbase Sciences Branch, Air Force Research Laboratory, Tyndall Air Force Base, FL, USA 

Many systems found in Nature or assembled in a laboratory exhibit hierarchical structure or organization. In the assembly, aU of the individual elements are connected in some manner. In a family, that connection is shared genetics in a complex structure, physical links hold all of the elements together. In another sense, one may assume that all subelements serve the apex or purpose of the hierarchy. For example, individual cells differentiate to yield complex organisms and all the pieces of a corporation coordinate to generate profit. 

Extending that metaphor of structure and function at each hierarchical level, materials possessing such architectures are oftentimes presented as a model for bionanocomposite materials. The analogy is particularly fitting in instances in which bionanomaterials are coupled with bulk material to form a component such as an electrode or transducer. All the elements (catalysts, interfacial associations, nanomaterials, bulk materials) must be properly integrated to move electrons from the outermost element throughout the hierarchy. In such a constract, the performance of 

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