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Hydrogen is not a primary fuel; one cannot win it from reserves by quarrying, mining, drilling or concentrating, as its velocity at ambient temperatures exceeds the escape velocity of this planet. Hydrogen is a secondary fuel: an energy carrier, equivalent to electricity. Generation of hydrogen for use as a fuel involves obtaining primary energy from somewhere else with which to make it.

There is a place for hydrogen in providing portable energy sources in the near future and further developments in this field are potentially very exciting.

Alternative Storage and Purification of Hydrogen using Palladium

"Palladium has the uncommon ability to absorb up to 900 times its own volume of hydrogen at room temperatures. It is thought that this possibly forms palladium hydride (PdH₂) but it is not yet clear if this is a true chemical compound.

When palladium has absorbed large amounts of hydrogen, it can swell up, like a sponge full of water, visible to the naked eye."

- Source: Wikipedia

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"Palladium is permeable to hydrogen at a temperature of 240° C and upwards. It absorbs hydrogen and other gases, the heat of occlusion being 4640 calories per gram of hydrogen. The occluded hydrogen is strongly bound to the metal, only traces of the gas being given off on standing in vacuo, but it is easily removed when heated to 100° C.

T. Graham (Phil. Mag., 1866–1869) was of the opinion that the occluded hydrogen underwent great condensation and behaved as a quasi-metal (to which he gave the name "hydrogenium"), forming an alloy with the palladium; but L. Troost and P. Hautefeuille (Ann. Chime phys., 1874, (5) 2, p. 279) considered that a definite compound of composition Pd2H was formed. The more "recent" work of C. Hoitsema (Zeit. phys. chim., 1895, 17, p. 1) however, appears to disprove the formation of a definite compound (see also J. Dewar, Phil . Mag., 1874, (4) 47, pp. 324, 342).

A palladium hydride was obtained by Graham by the reduction of palladious sulphate with sodium hypophosphite. It is an unstable black powder which readily loses hydrogen at 0° C. C. Paal and J. Gerum (Ben, 1908, 41, p. 818) have shown that-when palladium black is suspended in water, one unit volume of the metal combines with 1204 unit volumes of hydrogen..."

- Source: Online Encyclopedia

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"The discovery of palladium's remarkable ability to absorb hydrogen have since lead to uses which take advantage of this affinity. As a thin membrane, palladium will allow hydrogen to permeate through the membrane, but block all other gases. The further discovery of the stability of palladium-silver alloys and the ability to manufacture membranes of these alloys made hydrogen purification using palladium–silver membranes possible.

The mechanism of hydrogen involves a series of steps:
1) adsorption
2) dissociation
3) ionization
4) diffusion
5) reassociation
6) desorption

Several molecules of hydrogen and nitrogen atoms are on the metal surface. Within the metal, hydrogen loses its electron to the palladium structure and diffuses through the membrane as an ion (or proton). At the exit surface the reverse process occurs.

Palladium-silver membrane based hydrogen purification is used in many applications including semiconductor manufacturing. In particular, these membranes have wide spread use in the compound semiconductor industry, where the absolute purification of hydrogen is critical. When coupled with an effective purge system, a palladium-silver membrane based hydrogen purifier will give years of reliable service.

For the purification and/or separation of hydrogen from gas mixtures, the palladium alloy system offers a number of attractive features; the foremost of these is the quality of the ultra pure hydrogen itself. The diffusion cells involve no moving parts and the intrinsic value of the noble metal represents a recoverable investment.

Source: Johnson Matthey & Stillwater Palladium

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Worcester Polytech has undertaken significant research into catalytic hydrogen purification and fuel-cell research. Check out their website here.

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Why not HOD (hydrogen on demand) www.waterpoweredcar.com