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back to article Hydrogen on demand from silicon nanospheres - just add water

“Instant energy, just add water” – you might expect the expression under an ACME label in an old Warner Bros cartoon, but not from a University. However, researchers at the University of Buffalo in New York have demonstrated that nano-particles of silicon react with water to produce the non-toxic silicic acid and release …

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Boffin

Geometry fail

"Geometry is the key to the performance of the 10nm nano-spheres, which present the maximum possible surface area (relative to their size) to the water."

As any fule kno, a sphere offers the minimum possible surface area to volume ratio. For example, the surface area could be increased by drilling a hole through the middle of the sphere, which would also decrease the volume. Things like activated charcoal work by having a very high surface area/volume ratio. If you look at these particles under a microscope you will see that they have a sponge-like structure.

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Thumb Up

Re: Geometry fail

But lots of tiny spheres give a higher surface-to-volume ratio than a single sphere with the same mass, which is (I think) the idea.

The way my Dad explained it to me when I was a nipper was something like: "If you take a big lump of ice* and split it in half, you've got the same volume of ice, but two whole new surfaces where you split the halves apart. Now split those halves in half, and you've got the same volume again, but some more new surface. Keep making the chunks smaller, and you increase the surface area while always keeping the volume the same. Now go find me the formula..."

* We were talking about big ice cubes vs small ice cubes, as I remember...

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Meh

> Rather, they see the phenomenon as having potential as a portable energy source.

So - just like every other method used to produce the gas. Still dependant on a real energy source with all the angst that entails.

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Holmes

Solar plant by the Red Sea or in South Africa or Western Australia?

All these are doable. And silicon nanospheres sound a whole lot more transportable than lithium ion batteries.

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Re: silicon nanospheres sound a whole lot more transportable than lithium ion batteries.

And less likely to explode, burn, or leave nasty contaminants behind.

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Anonymous Coward

"So - just like every other method used to produce the gas."

So let me get this right - you were expecting a miracle ?

Sorry this universe has only 1 set of thermodynamics - you'll have to wait for another

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Happy

Desert

Sahara Desert = Loads of Silica + Loads of Solar Energy = A very big load of easily transportable nanoballs made very cheaply*, just add water for hydrogen on demand anywhere in the world.

* Not counting setup costs which would be considerable but could be recovered over many years.

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Meh

Re: Desert

Yeah, but that would hand over production to evil muslims, remember?

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Re: Desert

Cheers Badvok, for some positive thinking.

Well, once yo make one solar furnace, you can use that to melt glass for mirrors to make further furnaces. You could create other glass parts, perhaps those moisture-recycling enclosures that have been tested in arid deserts for growing food.

It doesn't just have to be the Sahara, there are other deserts to choose from.

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Off track

This topic has gone way, way off track. From bitching about the 'failures' of fuel cells to fake green credentials, the El Reg usual suspects have been remarkable slow in picking up the key parts of this storey.

1) You can carry the energy equivilent of 45l of Hydrogen in a one once package

2) Nobody is going to care if you spill some.

The 'failure' with fuel cells has always been the difficulty in supplying them with hydrogen in a safe and convienient manner. There use in cars (or laptops) currently requires distribution and storage of very highly compressed, and massivly explosive, pure hydrogen. This technology potentally removes that problem by allow the hydrogen to be created on demand requiring only locally sourced water.

The 'green' argument around energy use is a complete distraction here. Even if the production of the raw materials was very expensive, the 'green' question we should ask is if it is less expensive then the current ways of solving these problems with fossil fuels, when the production, distribution, storage and safety are also factored in.

A car using this technology would produce no pollution in use. To recharge it would simply empty its (non-toxic) waste tank, refill its fresh water tank, and top up on catalyst. Oh, and it doesn't use any non-renewables. What is not to like about this idea?

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Safe to transport?

Hang on a minute: this 10nm silica reacts with water to produce hydrogen gas, so it think transporting it is going to require careful waterproofing. You're not going to cart it around in open-topped railcars on a rainy day, that's for sure...

OK, there's established systems in place for bulk powders (like gypsum, for example) that react with water, but that will add to the costs. Perhaps to a level comparable with fuel tankers?

Oh, and don't eat it (unless you're a firebreathing act...)

So if it's as expensive to produce than petrol, just as tricky to transport and produces a waste product that doesn't just blow away in the wind, is it really any benefit? Maybe when the oil runs out the economics will get better...

I was hoping that the 10nm silicon would be a catalyst, rather than consumed by the process. Now *that* would be a win, even if it required regeneration every thousand litres of water or something...

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Boffin

Re: If the silicon acted as a catalyst

Then the little nano spheres would give off both hydrogen *and* oxygen.

I'll leave figuring out why this is a bad thing as an exercise for the reader.

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FAIL

It won't happen

You do all realise that this won't happen, who will relase a system that you can fill from your tap, or fo the purist from water condensed from your steaming kettle, theres no money in it.

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Re: It won't happen

The micro-spheres are the consumables. You make money by producing, transporting and selling them... and probably some water-purifying kit or system cleaning stuff as well.

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Bah!

For a minute there I thought the domestic fuel cell had just become an affordable reality and the chains of the Long Island Power Authority were a thing of the past.

Oh well.

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Paris Hilton

If you want powdered silicon...

just go to to your local silicon wafer fabrication plant and bring your dustpan and brush. There must be dust generated when all those silicon wafers get sliced up into individual chips (cleavage). Stop sniggering at the back!

http://en.wikipedia.org/wiki/Wafer_(electronics)

Paris, obviously.

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Happy

Re: If you want powdered silicon...

"just go to to your local silicon wafer fabrication plant and bring your dustpan and brush. There must be dust generated when all those silicon wafers get sliced up into individual chips (cleavage). Stop sniggering at the back!"

Historically about 1/3 of the whole boule gets lost in the sawing stage.

However with the interest in solar cells people have tightened things up and I think wire saws have less "kerf" loss.

But it will be semiconductor grade. Now that you mention I wonder what people do with it now.

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