Cryo-adsorbed gas storage in carbon materials

Hydrogen molecules may adsorb not just to metal surfaces, but also to surfaces of various solid materials including carbon, qualitatively following an adsorption and/or chemisorption curve of the type shown in Fig. 2.1. Ad- 

The use of nanotubes as the carbon material attracted some attention a few years back. Flowever, it has become clear that nanotubes cannot store hydrogen gas in its voids, but only as adsorbed to the sides, implying a storage capability no greater than that of any other carbon surface (in fact smaller due to the curvature of the surface) (Zhou et al., 2004). 

Surface absorption of hydrogen on metal surfaces is a well-known phenomenon in the electrodes of batteries. It may also be at work for electrodes made of nano-structured carbon and accomplishes nearly the same mass percentage as cryogenic storage for suitable electrolytes, but at ambient temperature. Charging or discharging takes several hours or even days, so the concept is unsuitable for use in cars (Jurewicz et al., 2004). 

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