Graphite Impregnation

How high is the sky?

Metal hydrides, such as MgH₂, NaAlH₄, LiAlH₄, LiH, LaNi₅H₆, TiFeH₂ and palladium hydride,

Could be an answer if we knew what the question was.

Sorry if I was not clear in the first question everyone. I want to be able to store as much hydrogen as possible within a metal or other compound that mimics titaniums properties like the re-absorbtion of hydrogen. Yes I mean to store it by volume and would like to take the hydrogen out either by vacume or by electrolysis. Also I want to thank all of you guys and gals for helping me with this question.

I am not restricted to just metals, I asumed metals would be best, I dont know what STP means, electrical potential can be used to extract through electrolysis and to replenish if possible. The reason I picked Titanium a metal, is because I read that it readily absorbs as much as it once stored when the titanium was made.

STP = Standard temperature and pressure, 0°C, 1bar.

Thanks for clearing that up but no I will be using a vacuume or electrolysis or maybe even pressure.

Lithium Borohydride LiBH₄, or Magnesium Iron Hexahydride Mg₂FeH₆ might also be answers, offering very high hydrogen per mass and hydrogen per volume, respectively.....though with out being constrained by other criteria, Dihydrogen monoxide might also be an answer, as it also offers high hydrogen density in volume and per mass, and it is cheap and abundant, though it isn't without dangers.

If I put Dihydrogen monoxide in a vacume chamber how could I seperate the pure Hydrogen?

Electrolysis is one way.

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Not many people call DHMO 'Dihydrogen Monoxide'... I was pulling your leg a little there...It could also be called hydric acid, or hydronium hydroxide.

How would you use electrolysis in Dihydrogen Monoxide?? Is it safe and is it easier to separate the gases?

Yes. Look it up in Wikipedia, Mildred.

DHMO indeed! Amazing stuff. The MSDS mentions donning protective eyewear and lab coat but, for the life of me I cannot find any reference to the regulation reagent-grade galoshes.

Please advise.

Any colour you like, boss.

Oh my. I've just hit the jackpot. Tank you, tank you, tank you!

I think using electric potential, palladium can hold a significant amount, though there may be alloys or complex hydrides that do a better job.

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To get a better answer, you need to define the question a little bit more precisely....

Hold the most hydrogen per volume or mass? At STP or other conditions? Can electric potential be used? What are the requirements, if any, for the hydrogen to come back out? How reactive can the material be?

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Are you restricted to just metals?

not restricted to metals, do not know what STP is and hydrogen per volume and electric conditions can be used

The obvious but impractical metal that will retain the most hydrogen will be metallic hydrogen. I suspect that your much more interested in hydrogen storage for reuse. Now if you wanted to really learn about this cutting edge field then you should peruse a few of these.

I am interested in metalic hydrogen as much as I am in hydrogen storage. Because under a vacume the Metallic hydrogen will give away some of its hydrogen just as water under a vacume am I correct or am I wrong saying this?

When you reduce the pressure in a container holding water, in an attempt to create a vacuum, water will flash to steam to fill the volume, but it won't evolve hydrogen gas unless there are some other things happening. The steam will be the same molecular formula, just more widely spaced.

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It might be a good time to review your requirements for what you are trying to accomplish.

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For example, if this were intended to operate in a hydrogen powered car, there are several requirements that need to be considered in conjunction.:

-Considering only hydrogen per volume isn't enough, because you don't want a huge weight penalty, so you need to also consider hydrogen per mass.

-Requirements for storage. Cryogenic conditions, extremely reactive/corrosive materials, and requirements for large continuous voltage potentials all present different challenges for a vehicle.

-Availability/expense of materials and fabrication.

-Efficiency of the process of charging and discharging the hydrogen from the system.

-Safety considerations. Some of these metal hydrides are very energy dense and reactive, LiBH₄ is a perfect example. Being in a traffic accident with the risk of a tank of that stuff rupturing near me would be quite unsettling. It isn't impossible to render reasonably safe, but it is a big consideration. and might make that avenue prohibitively expensive.

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I don't know what your application is, but whatever it is, it is a good idea to develop a solid description of all the requirements.

Yes and I can put a one way valve to direct the steam into the next chamber that is between 650 and 870 faranheit and should be able to seperate the two, shouldnt I? Or at least evaporate the water?

I am trying to build a combination hydrogen generator from using a vacuum, electrolysis, as well as a possible small custom built coal gassifier that can be used at the same time or they can be used one at a time, the entire system I am designing on a 4X8 trailer or a 6X12 trailer. I am just hoping for some help from you whiz kids. I know how to make hydrogen gassifier from welding several tanks together and it is a pain to get it perfect, I can build a HHO that can make so much gas that you have to burn the access gas, I am ne to the vacuming part to get hydrogen from water, but I dont think water will flash if you have a fine tune precision knob opening the vacume, please correct me if I am wrong. But this plan I have I estimate that I will build up to 5 different versions to get it smaller each time until it does fit on a 4X8 trailer, and I can haul it anywhere and have instant power.

Oh, never mind. Are you familiar with Mr. Toad from Kenneth Grahame's book "Wind In The Willows"? Have a nice ride.

Are you familiar with curious George?

Why not chuck a big ol' marine battery in that sucker and keep it topped-off with a photovoltaic (solar) panel? If you need A.C. hook an inverter to it.

Sheesh, mate, at this rate you won't have time to tow your trailer anywhere!

Anhydrous Ammonia NH₃ and Methane CH₄ (or possibly other hydrocarbons that offer better density) are two additional ways to store hydrogen that might be worth considering.

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These are well characterized hydrogen dense substances with well understood fairly simple ways of extracting hydrogen.

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Steam reformation is commonly used to generate hydrogen gas from methane. The DOE did some experiments on steam reformation in cars in the 70's I think.

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Hydrogen gas can be extracted from ammonia numerous ways, one example would be a reaction with lithium.

Thank you for your wild out of the park answer. I love it. But I was born in 74, could you tell me what experiments they tried on steam reformation?

Steam reformation of hydrocarbons is a mature technology. It is the process by which most hydrogen is produced today. Here is a link that provides a decent overview.

how do you extract hydrogen from amonia fast?

Fast is relative. How fast? Gaseous ammonia passed over molten lithium will yield hydrogen gas. You can increase the rates by increasing the contact and temperature up to a point.

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Ammonia seeks equilibrium with hydrogen gas and nitrogen gas. This is more apparent at high pressure and temperature. What this means is that at high temperature and pressure any reaction that removes nitrogen from the balance will cause a shift that produces an excess of hydrogen while the ammonia shifts to attempt to make up for the low levels of nitrogen.