Unlocking Nature's Hydrogen: An Inexpensive Metal Catalyst

[banerjeerupak]

I have heard about this metal catalyst which splits hydrogen and oxygen on interacting with water. i was a bit surprised when i came to know that this is a cheap metal and readily available.
Can you give me the name of the metal catalyst so that i can conduct expt in my labs.

 

[mrjeffy321]

I don't know if this is what your referring to, but if you heat metals up, really really hot, and stick them in water, it breaks the water down into Hydrogen gas and Oxygen gas. The Oxygen gas then Oxidizes the metal and the Hydrogen gas escapes into the atmosphere, but since it is so hot, then combusts with the Oxygen in the air.

I have seen this done in a video before, while someone is making a [samuri] sword, they heat it up red hot, then dunk it water, and you can see flames coming up out of the water.

 

[Mattara]

I have never heard of a metal catalyst doing such at STP. banerjeerupak. are you sure that it wasn't from some crackpot place/site?

 

[mrjeffy321]

banerjeerupak, are you sure it produces both Hydrogen and Oxygen gas?

If you loosen the requirements to just producing Hydrogen gas, then it is easy. Just place a more active metal into water (a metal above Hydrogen on the activity series) and the metal will react to produce Hydrogen gas and a metal Hydroxide.
Sodium is an excellent example of this, put a chunk of Sodium metal into water and it will expload due to the intense heat of the reaction combustion the Hydrogen gas which is produced, leaving behind NaOH in solution.

If you look at the activity series, you can see that there are several fairly common metals that will do this, although the lower down you go, the slow the reaction becomes.
http://www.chem.vt.edu/RVGS/ACT/notes/activity_series.html
The alkili metals on the periodic table will easily replace the Hydrogen from water, alkiline Earth not quite as fast, and when you get really low, metals like Tin and Lead do it so slowing it is negligible.

 

[banerjeerupak]

ok i really think that i made a mistake. anyway it must have been just the production of hydrogen. another question has cropped up in my mind. that is if we can burn hydrogen without explosion. the hydrogen that has been released, would be an excellent source of heat.

 

[nazgjunk]

Unfortunately it is very hard to control the burning of hydrogen. You /are/ right, it would be an excellent source of heat. since the thermolysis of water happens at 1500 C, reversing would obviously create huge amounts of heat. The thing is, that heat is probably one of the reasons hydrogen explodes rather than just burns. The only way I could think of would be to go slow on the oxygen to control the reaction, but I'm not sure if this is profitable.

 

[mrjeffy321]

I have heard of people using Hydrogen as a substitute for natural gas in grills.
In theory, it is possible as long as you control the flow of the gas and make sure not to mix it with Oxygen until it is ready to burn.

 

[Paula]

mrjeffy, what would happen to salt in this situation, as in seawater density 1.02 (or something)?

 

[mrjeffy321]

The situation of placing a much more reactive metal (like Lithium for instance) into water to release the Hydrogen?

The salt would remain behind in solution, assuming it does not react with the metal. The salt should not be affected by the reaction between the water and the active metal, the water will be split up, leaving a Hydroxide behind. Eventaully, it might get to the point where the remaining water will not be enough to keep everything in solution, so stuff might start precipitating out.

 

[Sid Greenfiel]

maybe you are talking about photo catalysing..

i.e. using visible light to directly split water into hydrogen and oxygen.

try: http://www.nature.com/nature/journal/v440/n7082/abs/440295a.html
as a starting point.