Hydrogen storage porous carbon materials

Tagaki H, Hatori H, Soneda Y, Yoshizawa N and Yamada Y (2004), Adsorptive hydrogen storage in carbon and porous materials . Mater Sci Eng B, 108, 143. 

Storage is an essential condition in the development of hydrogen-fueled vehicles. In this regard, porous carbon materials have attracted considerable attention as attractive candidates for hydrogen storage due to their good adsorptive capacity, low density, low cost, and high surface area (Jianwei et al. 2012). 

Concurrent stream of the development of nanomaterials for solid-state hydrogen storage comes from century-old studies of porous materials for absorption of gasses, among them porous carbon phases, better known as activated carbon. Absorption of gases in those materials follows different principles from just discussed absorption in metals. Instead of chemisorption of gas into the crystalline structure of metals, it undergoes physisorption on crystalline surfaces and in the porous structure formed by crystals. The gases have also been known to be phy-sisorbed on fine carbon fibers. 

Because of their biocompatibility, chemical stability, high thermal and electrical conductivity, sorption ability, tuneable surfaces area, pore-size distribution and straightforward functionalization chemistry, porous carbons have found application in diverse topical areas such as sensors, fuel cells, hydrogen storage, and sorption.39 11 One particular property that distinguishes porous carbon from porous silica materials is the electrical conductivity of the former that has no counterpart in siliceous-based scaffoldings. This feature opens the route for certain applications... 

The hydrogen storage values of PIMs and HCPs are still smaller than for many porous carbon samples. However, PIMs and HCPs have only recently been investigated for H2 adsorption and further modifications of these materials can lead to an enhancement of their hydrogen storage capacity at cryogenic temperatures. 

The activation of char, obtained from the pyrolysis of post-consumer PET bottles, with carbon dioxide at 925°C leads to highly porous materials. After a burn-off of 76% a BET area of 2500 m is reached. This material shows similar or better hydrogen adsorption properties than high-tech carbon materials such as nanotubes [40]. It was possible to charge the carbon with 2.3 wt% hydrogen at — 196°C. This fact opens the way for the use of this low-cost material as hydrogen storage. 

Taking into account the underestimated advantages to operate in aqueous electrolyte, it seems also important to look for other applications of carbon materials where the unique combination of electrical conductivity, surface functionality and porous texture may be useful. Such applications as electrochemical hydrogen storage [116, 117], asymmetric supercapacitors [118] open future perspectives where aU the information previously collected on other systems will be useful. 

Porous carbon-nanofiber-supported nickel nanoparticles also can be used as a promising material for hydrogen storage. It was found that the amount of hydrogen stored was enhanced by increasing nickel content [7] (Fig. 8.13). 

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