CO
2 was absorbed into C
60-C
70 binary solids at room temperature using a commercially available autoclave. The solids were then immersed in liquid CO
2 for 24 h at a gas pressure of 5 to 6 MPa, and the degree of CO
2 storage was evaluated by infrared (IR) spectroscopy and X-ray diffraction (XRD). CO
2 was detected in pure C
60 by IR measurement, and the stoichiometry was estimated to be C
60(CO
2)
0.34 based on the increase in the lattice parameter. Although no trace of CO
2 storage was detected for pure C
70, the addition of C
70 to C
60 at a mole fraction of up to 0.16 did not appreciably degrade the storage capacity of CO
2 from that in pure C
60. The stability of CO
2 trapped in solid fullerenes is explained in terms of geometrical considerations based on hard-sphere packing at octahedral sites.
View full abstract