Chapter 23 - Advances in the Use of Carbon Nanomaterials in Catalysis

Abstract

This chapter presents an overview of carbon nanotubes (CNT) and carbon nanofibres (CNF) chemistry, with a deeper focus on their applications in catalysis, both as a support and as a catalyst. Carbon nanotubes (CNT) and carbon nanofibres (CNF) are cylindrical or tubular carbon formation with radii on the nanometre scale and lengths of up to several microns. The catalytic CVD processes allow the formation of CNF and CNT with high selectivity and few impurities and are more suitable to large-scale processing of these 1D materials. The different catalytic applications presented in this chapter confirm the potential of the carbon nanomaterials to be used as catalyst supports either in gas-phase or in liquidphase media. Metals supported on carbon nanostructures exhibit unusual catalytic activity and selectivity patterns when compared to those encountered with traditional catalyst supports. The extremely high external surface area displayed by these nanoscale materials significantly reduces the mass transfer limitations, and the peculiar interaction between the deposited active phase and the surface of the support were advanced to explain their catalytic behaviors. The existence of an electronic interaction between the carbon nanomaterial surface and the coated species could also affect in a significant manner the final properties of supported species. Apart from the direct use of these nanomaterials as catalyst supports other useful applications of these materials, especially self-supported CNT, and may also be expected in the synthesis of several 1D materials (metal, oxide or ceramic) which could find some new applications in catalysis but also in several areas of the emerging nanotechnology field.