Hydrogenation of Carbon Nanotubes and Graphite in Liquid Ammonia

Abstract

We have prepared hydrogenated single-wall and multiwall carbon nanotubes, as well as graphite, via a dissolved metal reduction method in liquid ammonia. The hydrogenated derivatives are thermally stable up to 400 °C. Above 400 °C, a characteristic decomposition takes place accompanied with the simultaneous formations of hydrogen and a small amount of methane. Transmission electron micrographs show corrugation and disorder of the nanotube walls and the graphite layers due to hydrogenation. The average hydrogen contents determined from the yield of evolved hydrogen correspond to the compositions of C11H for both types of nanotubes and C5H for graphite. Hydrogenation occurred even on the inner tubes of multiwall nanotubes as shown by the chemical composition and the overall corrugation. The thermal stability and structural results suggest the formation of C−H bonds in nanotubes and graphite.