POLYATOMIC-GAS STORAGE IN FULLERENES-CO2 FORCED INTO THE C-60 LATTICE

Carbon dioxide has been forced into the lattice of C-60 using Hot Isos tatic Pressing (HIP) at temperatures between 350 and 500 degrees C, an d with 170 MPa of CO2 gas, and a HIP period of 60 h. Using both Therma l Gravimetric Analysis (TGA) and powder X-ray diffraction with Rietvel d analysis, the CO2 has been shown to occupy the octahedral interstiti al sites with an occupancy of similar to 0.8. Infrared spectroscopy co nfirms the presence of trapped CO2. Over a couple of weeks at room tem perature, the material slowly loses CO2 to give a stoichiometry of sim ilar to 0.62. After this, it seems to be stable to further loss for se veral months. (C) 1998 Elsevier Science Ltd. All rights reserved.