Carbon nanotubes as next generation catalysts for heterogeneous partial oxidation and aldol condensation/ketonization processes.

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Carbon nanotubes (CNT) are the best known nanomaterials and their properties have attracted a significant attention from the scientific community. Applications of these materials include a wide range of areas, from tissue engineering to flat panel displays. In the specific field of heterogeneous catalysis the use of CNTs opens the possibility of nanoengineering catalytic sites for specific chemical transformations or industrial relevance. Moreover if nanotubes are used as the only component of an industrial catalytic formulation they offer the prospect of a metal free catalysis technology for sustainable chemical transformations. Most of the current commercial catalytic formulations are based on expensive not renewable inorganic materials such as platinum, palladium, or rare metal oxides. While just a few years ago the use of CNTs as heterogeneous catalysts was cost prohibitive, improved CNT synthesis methods have driven costs to levels comparable or even lower to current catalytic systems based on metals and metal oxides. CNTs are indeed rather attractive as heterogeneous catalyst, due to their hollow geometry and high surface area (they resemble a seamless hollow cylinder with very high aspect ratio). More importantly, the introduction of chemical groups into the nanotube walls can provide catalytic functionalities required for specific catalytic transformations of industrial significance, including those needed for the production of fuels and fine-chemicals from renewable resources. The morphology of these catalytic functionalities depends only on the nanotube surface properties and the protocols used for the nantotube chemical functionalization. Hence a careful control of the chemistry of CNT walls is critical for the development of CNT-based catalysts. However, protocols needed to create the chemical functionalities required for superior catalytic performance of CNTs in heterogeneous processes have yet to be implemented. The proposed research program will carry out the necessary steps to extend our ability to develop this scheme and develop the fullest range of CNT-based catalysts.