ZB 10 - Soft Condensed Matter (R. Holyst)

Storage of hydrogen at 303 K in graphite slitlike pores from grand canonical Monte Carlo simulation

Author(s): Kowalczyk, P and Tanaka, H and Holyst, R and Kaneko, K and Ohmori, T and Miyamoto, J
Title: Storage of hydrogen at 303 K in graphite slitlike pores from grand canonical Monte Carlo simulation
Abstract: Grand canonical Monte Carlo (GCMC) simulations were used for the of the hydrogen adsorption in idealized graphite slitlike In all simulations, quantum effects were included through the and Hibbs second-order effective potential. The simulated excess isotherms of hydrogen were used for the determination of total hydrogen storage, density of hydrogen in graphite slitlike distribution of pore sizes and volumes, enthalpy of adsorption mole, total surface area, total pore volume, and average pore size pitch-based activated carbon fibers. Combining experimental results simulations reveals that the density of hydrogen in graphite pores at 303 K does not exceed 0.014 g/cm(3), that is, 21\% of liquid-hydrogen density at the triple point. The optimal pore size the storage of hydrogen at 303 K in the considered pore geometry on the pressure of storage. For lower storage pressures, p < the optimal pore width is equal to a 2.2 collision diameter of (i.e., 0.65 nm), whereas, for p congruent to 50MPa, the pore is equal to an approximately 7.2 collision diameter of hydrogen 2.13 nm). For the wider pores, that is, the pore width exceeds a collision diameter of hydrogen, the surface excess of hydrogen is constant. The importance of quantum effects is recognized narrow graphite slitlike pores in the whole range of the hydrogen as well as in wider ones at high pressures of bulk hydrogen. enthalpies of adsorption per mole for the considered carbonaceous are practically constant with hydrogen loading and vary within narrow range q(st) congruent to 7.28-7.85 kJ/mol. Our systematic of hydrogen adsorption at 303 K in graphite slitlike pores gives insight into the timely problem of hydrogen storage as the most source of clean energy. The calculated maximum storage of is equal to approximate to 1.4 wt \%, which is far from the States Department of Energy (DOE) target (i.e., 6.5 wt \%), thus that the total storage amount of hydrogen obtained at 303 K in graphite slitlike pores of carbon fibers is not sufficient yet.
Pages: 17174-17183
Journal: JOURNAL OF PHYSICAL CHEMISTRY B
Volume: 109
ID: ISI:000231809300024
Year: 2005
DOI: 10.1021/jp0529063