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 …
It's certainly not "free energy" but it does lead to an interesting question of efficiency. If they can make the whole process more efficient than many existing processes and can get the needed power out of it then it could become an interesting alternative for high drain devices such as electric wheel chairs. It would be pretty nice to replace a lot of battery weight with a small refillable water tank and a packet of silicon balls.
Powering wheelchairs ... a worth goal, for sure. However, I suspect that the silicon spheres will come in at many thousands of dollars for a sufficiently sized (and single-use) battery. Given the current healthcare spending climate, I strain to see the broader appeal in that particular market.
I dunno, now they've got a proven concept the "big money" has the potential to bring a lot of resources to bear on making the spheres cheaply. When you think about it, it's nuts that you can buy a knock-off tablet when for under £100, considering the technology hidden within, not to mention assembly and distribution costs.
Silicon is also marvelously abundant - no danger of it becoming a costly material in its own right.
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"bear on making the spheres cheaply"
The silicon is just an energy carrier - you need to put energy in to get silicon from silicon dioxide. Generate the hydrogen and consume it as efficiently as possible and you might get back a modest proportion of the input energy. There's no way round that it's just chemistry and thermodynamics. If you can get really cheap energy it might be useful for certain niche application - basically it allows you to store the equivalent ~45L of hydrogen in 28g of silicon (+water)
Energy costs dominate this with the proviso that making the nano-silicon particles may in fact dominate the process. Material costs are irrelevant as the silicic acid can be converted back to silica if necessary
The minimum energy cost is ~1MJ/mol (=28g) and may be a lot more
"Powering wheelchairs ... Given the current healthcare spending climate, I strain to see the broader appeal in that particular market."
OK, How about powering battlefield exo-suits for the military, then?
Let's compromise, and power battlefield exo-suits for the disabled. Problem solved!
The issue, the guy said was that the FASTEST reaction was with 10nm silicon spheres......
It does not mean that you just can't simply cast up HUGE double mattress slabs of silicon, and have them churn away - ever so slowly into hydrogen producers...
Personally I can't think of anything better than running silicon oxide powder, through a solar concentrator furnace, extracting the oxygen and then repeating the process.
This is basically very fine high quality sand. You might be able to sell it as a chromatography stationary phase, as a very fine abrasive material or use it in the production of glass product I suspect.
Still not convinced you can make the original spheres sufficiently cheap though.
> Is there any use for the silicic acid produced?
It might be used, together with trace elements, to enhance carbon capture by the oceans. Shortage of silicon is one of the limiting factors in the growth of diatoms. These capture carbon dioxide and take it down to the ocean floor when they die. Quite a lot would be needed however.
See, e.g.
http://www.sciencedaily.com/releases/2013/01/130121192017.htm
Ah! It would have been good to know this months ago, for my ovariectomized model rats have fuck-all femoral bone to speak of.
I like that you've provided your reference* there, very thorough.
Davidoff
*Well, what the less-cautious among us would call a reference anyway.
The whole point of hydrogen cell technology is to use the hydrogen as the energy storage element. The 'green' principle is to generate the hydrogen from 'renewable*' sources such as a simple solar reactor. And then you have water as the waste material from the fuel cell.
But what they do here is expend a ton of energy from traditional sources to create silicon balls (at what level of efficiency??) then generate hydrogen by chemical reaction (at what level of energy efficiency?), then use the hydrogen to power a fuel cell. They are using the silicon as the energy storage element rather than the hydrogen, and then they have silica sludge as a waste product.
On the plus side, I suppose the silicon might be safer to store and manage than a hydrogen storage tank. But if it generates so much hydrogen when in contact with water, that doesn't sound like the sort of thing that I let the average user handle.
Dino
*good luck with 'renewing' that solar energy source
I think that the real point of this is that they can produce the silicon balls in a central location, ship them off to distribution points, and then use the easily transportable water + balls to power equipment. You could probably also feed the water coming out of the hydrogen fuel cell back into the silicon balls to reduce the amount of water you need to carry around.
If they can find a way to mass produce these balls, then they also have a source of purified ore that can be turned back into the balls.
I can just see going to a petrol station and swapping a 10*10*30 cm box in your car for a new one and carrying on, the petrol station would then recycle the silicon ore (or send it back for recycling on the delivery lorry).
> But if it generates so much hydrogen when in contact with water, that doesn't sound like the sort of thing that I let the average user handle.
Nor do you let the user introduce a whole tank of petrol to oxygen and fire... the carburetter and the cylinder do that.
It's still safer than having a tank of highly compressed hydrogen in your car.
>>> *good luck with 'renewing' that solar energy source
Dunno where you live, but round here we get a brand new solar energy source every morning, helpfully pushed into the sky by the great scarab beetle.
Of course there's always the risk we'll run out of virgins to sacrifice.
Hahaha, you have such a wonderully old fashioned view of all this!
Everybody knows that it isn't a 'new' energy source, it's the same one as yesterday! :) After the fiery sphere descends of an evening, it passes underneath the Earths disc, below the elephants standing on the back of the turtle and simply comes back up the other side. Scarab beetle indeed!
The other factor of 50 is the fact the original spheres were clumping, which is a known problem with this sort of work and which people researching in this area should be aware of. We're in emulsions, micelles and surfactants territory here.
Leaving aside the NSS aspect this has some key benefits.
a)It uses silicon and water to produce H2 directly. So no rare (or likely to become rare if usage grows) materials and a way to convert it to heat or electricity (both already exist for H2. The problem has always been converting the hydrogen carrier to hydrogen) b)The question is wast products are fairly harmless.
The downside are a) Making Silicon spheres this small on a commercial scale (tonnes, not grams) is likely to be tough and you have to ask does the energy balance work out. b)Can you re-cycle the wast product?
"Can you re-cycle the wast product?"
Yes, but you'd need to provide some more energy to dehydrate it - it's basically similar to silica gel that's used as a desiccant often in little bags with "do not eat" on them.
I've covered some aspects of the energy cost in a post further up the thread
(The whole business is a little like the old carbide process where calcium carbide + water produced acetylene on demand for portable lights.)
"(The whole business is a little like the old carbide process where calcium carbide + water produced acetylene on demand for portable lights.)"
I'd forgotten about this technology. It is remarkably similar. Too bad there is no well developed electrocatalyst for Ethyne.
I think people have been focusing on the Hydrogen aspect but the real gains are that you can leverage all that H2 fuel cell technology (which AFAIK is the most advanced in terms of catalysts, construction etc). It's cheap, high density, safe to carry and to dispose of. I think the nearest thing to it in terms of inert storage would be a thermal battery (which you would not want to be near when it's operating).
The raw materials (like carbide and water) are cheap and stable. I think the real jokers are a)Can you do this with "metallurgical" grade Silicon rather than semiconductor grade, which would knock down the mfg cost but increase the risk of catalyst poisoning b)How difficult is the mfg process. Spray nozzles and drop towers can produce things like shot gun fillings in high volume and I think Super Critical fluids can produce spheres below the nozzle diameter size (but I'm not sure how far) but 10nm is pretty small. c)Can you use straight water spraying on to a mound of this stuff to get the H2 out or do you need some elaborate (IE expensive) waster distribution system and d) How difficult is effective recycling. Now if you could convert the acid back into the Silicon form while retaining them as 10nm spheres you could spread the cost of their mfg over as many cycles as the process would support. But that's one big if.
"But that's one big if."
Absolutely. Si surfaces rapidly coat with SiO2 so I imagine the nanospheres would need to be made out of contact with air. On exposure to water I rather think they would change their shape rapidly and indeed if they didn't much unexposed silicon might be wasted or the reaction rate at least limited.
Overall this is just one scheme amongst others that could be used as a portable source of hydrogen.
@chemist
I like the low-tech aspect of cacium carbide.
I suggest using a powdered alkali metal (much cheaper to produce and transport than silicon nanoparticles). Potassium or sodium might not be acceptable, but what about calcium? It's plentiful, nontoxic and calcium hydroxide is benign.
Like silicon, you'd need to reduce it first, then keep it dry under an inert gas.
I don't want to refill anything. Water is a finite resource too, not to mention purified water sufficient to perform this trick and the silica needed to make it work in the first place.
I want something that will last 2000+ charges and still work without me having to top it up, like the £50 car battery I use as the most powerful example of this, or the Li-Ion in my laptop, or the £2 AA rechargeable. As soon as we get to the point of "just add" anything, that anything will become more expensive, especially if you have to do it every charge (sure, you can top up an - old - car battery with some purified water and even acid if you're determined, but it's literally an occasional thing compared to how often the battery is depleted and recharged - i.e. every trip - and with modern batteries you can literally have a car go for ten years of use and not require maintenance at all and still hold a full-enough charge in winter).
Hydrogen fuel cells hold no special place in my geek-heart. All you do is shift the product I have to buy from batteries (which I buy so rarely it hardly matters) to little fuel canisters to charge the batteries. And until those fuel canisters give me the equivalent of 2000 times the run time of a set of batteries, I'm still running at a loss there.
They may be "greener" (in some senses) but they are far from ideal and may even be worse than we already have (now we have to make fuel cells, and canisters that can hold a dangerous fuel safely, and the fuel itself - instead of just a battery). And from a consumer point of view, they have to have fuel be sold for literally PENCE before they become advantageous over conventional batteries (and how long before kids work out a way to make those fuel canisters explode by some trick, and they buy up the stock on Halloween?).
Fuel cells are a step backwards, until they can literally recycle (like a rechargeable battery) or do not exhaust their fuel over their lifetime.
There are plenty of uses for a 'refillable battery' although a generator is really a better name. Already large units are available for motorhomes and yachts that allow silent power production on a considerable scale for many weeks from cassettes of methanol ( not ideal I admit ). You could use solar or wind but the energy stored in even methanol is significant and allows for heavy usage in darkness.
An example here : http://www.youtube.com/watch?v=1vWvPwiQazI
A bit twee but it gives some of the current possibilities. As far as I can tell the running costs are ~~£2/day for a 600W unit
A car starting battery is a very poor example, because it is built to supply high current above all other considerations, and is hardly discharged at all in proper use. Try using one as a deep cycle battery and you'll be lucky to get ten decent charges from it as the plates fall apart and buckle.
A better example would be a deep cycle lead-acid "leisure battery". I don't know how long these last, but it isn't 2000 cycles and 10 years. On the other hand, lead-acid batteries nearly all get recycled, so it's not all bad.
So you don't put petrol into your car?
Hydrogen fuel cells are essentially a replacement for the cars engine and this would be providing the fuel for said engine. The reason that engines are preferable to batteries is that (and I'm sure you know this) the time cost to refill the fuel reservoir compared to recharging the battery is significant. As a use case compare the time it would take to recharge your car battery compared with filling it up with 20L water and a new canister of silicon balls.
As for Green, they are only as green as the fuel source used to create the hydrogen.
I see your point about the potential refill cost rising. But your already 'refilling' all your examples every time you plug in a rechargeable battery or start your car.
The difference is that traditional electricity generating tech is so commonplace that the cost is tiny. No new technology is going to be as cheap as entrenched interests. The trick is to out maneuver those interests and between innovation killing legislation and dirty tactics it is really hard to do.
Surely Fuel Cells should now classified as a total technology failure, as various companies have been promising/promoting this idea for years and it's come to absolutely nothing. I remember some of the Japanese backers years ago suggesting we fill our laptops with one liquid or another and they'll last for a full day. Yeah right.
And now this idea, with the expensive-to-make balls and associated waste material, it's actually a step backwards from the nonsense usually promoted. Consumers are not particularly interested in fuel cells for small devices, perhaps they have a future in cars and larger products, but in mobile devices absolutely not - just forget about it and invent better batteries that charge in seconds and last for days.
I'm sick and tired of hearing/reading about these new wonder technologies that offer 10x, 100x, 1000x better power/charge/recharge performance - but in a lab. Get this technology out in to the real world, or shut up about it...
What is it that you don't get about easily transported, safely stored hydrogen?
Would you rather fill your laptop up with a pressurised hydrogen gas tank?
Fuel cells for small devices may make sense in emergencies (where there is no leccy power) but given the amount of research and development that has gone into this area of technology, and the number of products that have so far come to market, it shows that fuel cells are, by and large, still a pipe dream.
And if/when a fuel cell product does come to market for small device, it will almost certainly sell in vanishingly small quantities, certainly nothing like the volume required to repay the R&D costs.
As for these nanospheres, it just seems like another opportunity to blather on about the latest nano-something as they have no obvious benefits over prior fuel cell technology, using more energy in the manufacturing process, and creating a potentially toxic waste product as part of the power generation process.
"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.
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...
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.
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?
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...
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.
"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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