Hydrogenization of fullerenes as a method of storage of hydrogen

IntroductionHydrogen is an ideal fuel with a high calorific value and a harmless combustion product - water vapor. Storage of hydrogen is one of the intermediate links in the life cycle of hydrogen from its production to... [ view full abstract ]

Introduction

Hydrogen is an ideal fuel with a high calorific value and a harmless combustion product - water vapor. Storage of hydrogen is one of the intermediate links in the life cycle of hydrogen from its production to consumption. The development of the most economical and efficient ways of storing hydrogen is one of the main technological problems of hydrogen energy.

Methods

In the present work the method of catalytic hydrogenation of fullerenes is considered. At the moment, carbon nanomaterials are used to store hydrogen due to its low specific density and high specific surface area: activated carbon, graphene, multi-walled and single-walled carbon nanotubes, fullerenes, etc. 

Results 

To determine the optimal regime for the hydrogenation of fullerenes at a hydrogen pressure of 12 MPa and a temperature in the range of 200-600°C, the mass of fullerite C60 is 0.501 g. First, vacuum conditions were created in the reactor, after which hydrogen was supplied to the reactor to pressure of 12.5 MPa and held for 4 hours. Then, the reactor temperature was raised to 200°C (at speed of 1° per minute) while the pressure in the reactor increased by 0.3 MPa (reaching 12.8 MPa). To stabilize the baro-temperature regime, the sample was kept for another 4 hours (T = 200°C, P = 12.8 MPa). At 480 minutes, the temperature rise in the reactor was continued from 200 to 600°С at rate of 0.125° per minute. 

Discussion

Increase in temperature can be explained by the decomposition of solvates formed during the crystallization of fullerite. It was found that the system reached its maximum interaction speed at 2150 minutes, which corresponded to temperature of 433°C. As a result, the temperature, at which the rate of interaction of hydrogen with the fullerene molecule is maximized, was clarified and the given value of temperature is in the range of 425-455°C, where the total hydrogen content is about 8.2% by weight. Further, the obtained hydrofullerites were studied using Raman microscopy. The results indicate that the obtained samples contain hydrogen atoms.