Role of Alumina Type In the Growth of Single-Walled Carbon Nanotube Carpets From Alumina-Supported Fe Catalysts

The crucial role alumina plays as a catalyst support in the growth of single-walled carbon nanotube (SWNT) carpets is unsurprising as it is a well known structural modifier or catalyst promoter in hydrocarbon reforming and ammonia synthesis reactions. Although a lot of studies have been carried out hitherto to explain the role of alumina and the Fe-alumina interaction in the these reactions, an important area of SWNT carpet growth that has not yet been studied explicitly is how the type of alumina (based on deposition method) affects the activity and lifetime of the catalyst, SWNT quality and selectivity, and the growth termination process. Using a combination of microscopic and spectroscopic techniques, we have provided new insights into the Ostwald ripening behavior, activity, lifetime, and sub-surface diffusion of Fe catalysts supported on different alumina types.