Protocol for High-Sensitivity Surface Area Measurements of Nanostructured Films Enabled by Atomic Layer Deposition of TiO2

Due to their nanoscale dimensions, nanomaterials possess a very high specific surface area, which directly informs their properties in energy conversion and storage and catalytic chemical transformation, among other applications. However, common laboratory scale samples of nanostructured films have a total surface area that is too small to measure by conventional techniques such as the Brunauer-Emmett-Teller method, although they may have high gravimetric surface area. The methodology presented here allows for accurate measurement of the surface area of nanostructured films of a variety of materials, and involves two steps: uniformly and conformally functionalizing the surface of the nanostructured film under study by an ultrathin titanium oxide adhesion layer through atomic layer deposition, and quantifying the amount of adsorbed dye molecules on the TiO2 coated nanostructure film. Carbon nanostructures, especially nanomaterials making use of the exciting properties of graphene, are under investigation by numerous laboratories around the world, and were therefore chosen as ideal materials for the demonstration of this procedure. In this research, two nanomaterials of high aspect ratio were chosen for this purpose: multiwalled carbon nanotubes and a covalently bonded graphene-carbon nanotube material termed graphenated carbon nanotubes. This method has been successful in studying films with total surface area as low as 20 cm2 and was additionally used to probe the underlying mechanisms of highly effective charge storage in high graphene edge density carbon nanomaterials.

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Author Charles Parker  

Author Jeffrey Glass Electrical and Computer Engineering