Comparative study of hydrofullerides C_(60)H_x synthesized by direct and catalytic hydrogenation

摘要

Hydrofullerides with hydrogen content up to 5 Wt.% were obtained by direct and catalytic reaction with H_2 gas. Hydrogen content was monitored in situ using gravimetric system and verified by chemical analysis ex situ. It was found that pure C_(60) reacts rapidly when exposed to H_2 gas at 673 K and 50-100 Bar. Gravimetric study of this reaction showed that hydrogenation is saturated at about 5 at.% of hydrogen. Mass of the sample goes through a maximum and with a longer reaction time its weight start to decrease. This proves that hydrofullerides with high hydrogen content are not stable and strong hydrogenation results in collapse of C_(60) molecules. XRD study showed that samples prepared by direct hydrogenation without catalyst retain an original FCC structure with increase of ceil parameter up to a=15.1A. Catalytic hydrogenation of C_(60) with H_2 gas results in decrease of the reaction temperature and formation of hydrofullerides with new crystal structure (suggestively sc).