Carbide-Derived Carbons: Effect of Pore Size on Hydrogen Uptake and Heat of Adsorption

Abstract

Cryoadsorption is a promising method of enhancing gravimetric and volumetric onboard H 2 storage capacity for future transportation needs. Inexpensive carbide-derived carbons (CDCs), produced by chlorination of metal carbides, have up to 80 % open-pore volume with tunable pore size and specific surface area (SSA). Tuning the carbon structure and pore size with high sensitivity by using different starting carbides and chlorination temperatures allows rational design of carbon materials with enhanced C-H 2 interaction and thus increased H 2 storage capacity. A systematic experimental investigation of a large number of CDCs with controlled pore size distributions and SSAs shows how smaller pores increase both the heat of adsorption and the total volume of adsorbed H 2 . It has been demonstrated that increasing the average heat of H 2 adsorption above 6.6 kJ mol -1 substantially enhances H 2 uptake at 1 atm (1 atm = 101 325 Pa) and -196 °C. The heats of adsorption up to 11 kJ mol -1 exceed values reported for metal-organic framework compounds and carbon nanotubes. Cryo-adsorption is a promising method of enhancing gravimetric and volumetric onboard H 2 storage capacity for the future transportation needs. Inexpensive carbide-derived carbons (CDC), produced by chlorination of metal carbides, have up to 80% open pore volume with tunable pore size and specific surface area (SSA). Tuning the carbon structure and pore size with high sensitivity by using different starting carbides and chlorination temperatures allows rational design of carbon materials with enhanced C-H 2 interaction and thus increased hydrogen storage capacity. Systematic experimental investigation of a large number of CDC with controlled pore size distributions and SSA show how smaller pores increase both the heat of adsorption and the total volume of adsorbed H 2 . It has been demonstrated that increasing the average heat of H 2 adsorption above 6.6 kJ/mol substantially enhances H 2 uptake at 1 atm and -196 o C. The heats of adsorption up to 11 kJ/mol exceed values reported for metal-oxide framework compounds and carbon nanotubes.

Development of Doped Nanoporous Carbons for Hydrogen Storage

“…The pore size distribution of TiC-CDC synthesized at 600 o C and 3 hrs (Fig. 5 of 47 ) was qualitatively similar to published data, 48 but the surface area was ~80% lower than published, likely due to the lack of complete removal of the TiC precursor. The synthesis temperature was then elevated to 800 o C and 1000 o C, but XRD indicated the TiC precursor was still present (data shown in Fig.…”

Structural prediction of graphitization and porosity in carbide-derived carbons

“…[5,6,7,8] At low temperatures, all carbides transform into a disordered microstructure, and with increasing temperature different levels of graphitization are observed. [2] Many carbide precursors, such as ZrC, Fe 3 C and TiC, produce graphite-like ribbons upon heat treatment above 1000…”

Hydrogen adsorption by perforated graphene

“…Nanostructured carbon materials have been considered as promising candidates for hydrogen storage applications due to high surface areas and chemical stability. [1,2] Activated carbons [3,4] , carbon nanotubes, [5,6] graphite nanofibers [7] and carbide derived carbons [8] have been actively studied for hydrogen storage applications during last decades. It is known that hydrogen uptake correlates well with the BET surface area and micropore volume for most of the high surface area adsorbents including carbon materials.…”