

Single-catalyst water splitter produces clean-burning hydrogen 24/7 - tessela
http://news.stanford.edu/news/2015/june/water-splitter-catalyst-062315.html

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ams6110
Worth being clear that splitting water into hydrogen gas for use as a fuel, no
matter how efficient, is still just another form of battery. If they really
are achieving >80% efficiency that's getting up there with the best Li ion
batteries, but hydrogen still presents a lot of handling and transport
complexities for use as something like a motor vehicle fuel. Probably best
used in large industrial scenarios, e.g. storing excess energy from solar or
wind, and fueling gas turbine generators at night or low-wind periods.

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userbinator
_but hydrogen still presents a lot of handling and transport complexities for
use as something like a motor vehicle fuel_

With this efficiency, it could be feasible to just split the water at the
point-of-use.

I'm reminded of the "run your car on water/save fuel" scams which involved
"HHO generators" \- basically the same thing - located in the intake manifold
and connected to a source of water and electricity from the car's electrical
system. This time, it might actually do something interesting...

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knodi123
> With this efficiency, it could be feasible to just split the water at the
> point-of-use.

Isn't it still a pretty slow process? Efficiency doesn't matter if it
generates a trickle of H, and you need a large fixed volume.

Splitting at point of use is silly anyway- why use power to split water into
hydrogen you can use for a fuel cell to generate power, _at the point of use_?

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bane
The engine could draw on a smallish stored reservoir of H2 for normal
operation. That reservoir could then be continuously supplied with H2 from the
process until it hits some pressure metric after which the system temporarily
turns off until the pressure in the reservoir dips below some threshold.

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knodi123
okay, so if we need a fixed volume X, and we have a reservoir of (1/2) X, then
we only have to wait on the slow trickle of the remaining 1/2 instead of the
full amount.

Plus, what do you think the H2 is for? Generally, we think about using it in a
fuel cell. Which generates electricity. And the idea of using electricity to
split out H2 in order to generate electricity, _all in one place_....

You're adding complexity, but I'm not sure you're actually improving on
simpler approaches.

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DannoHung
I know this is another article about electrolysis catalysts, but this one
actually seems pretty incredible. Does anyone know more about how far long
this lab group is in their research and whether or not there are any
commercialization partners at this stage?

Have they run tests for longer than a week? Have they seen any degradation to
the cathode or anode? Is there a reason to go beyond water electrolysis with
the electrochemical tuning process in terms of energy storage?

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stephengillie
My understanding (from reading the article) is that the single Li-ion battery
lasted for a week.

Considering that these are extremely common metals, I can't see why this
wouldn't be viable, even with anode/cathode degradation.

~~~
DannoHung
Maybe? The article was actually a little unclear on that. They may not have
been able to run the experiment longer than a week. The only comparison they
provide is the conventional catalyst which degraded significantly within 30
hours of operation.

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stephengillie
The device generates a lot of O2 as a "waste product" (obviously) so could
this be a viable way to oxygenate an atmosphere?

It's somewhat amazing that they can use such common metals for both catalysts.
Also it's remarkable that only 1.5V is required for the operation. That's a
common output voltage for solar panels. This design should be ripe for space
travel applications. (I think the current solution produces electricity by
recombining hydrogen and oxygen, so maybe this could also be an input for
that?)

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samstave
Assuming a planet has water, would it not be safe to assume it also already
has an atmosphere?

Unless - you have a nuclear powered device which melts trapped CO2 ice and
then generates O2?

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JshWright
Not really, no.

We're finding water (even liquid water) is actually _really_ common in our
solar system (and presumably, in the universe as a whole).

Breathable atmospheres, on the other hand, are pretty rare.

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imglorp
Might this have value as a desalinator/purifier? Hydrolyze some dirty/salty
water, then immediately recombine it in a fuel cell to produce some power and
fresh water.

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canvia
I had an idea the other day of using electrolysis at the bottom of an
extremely deep water filled shaft to generate gas bubbles that could be
harnessed to turn turbines as they rose to the surface.

Whether that could ever be more efficient than other power generation methods
I have no idea. I guess the initial construction and ongoing maintenance
requirements might make it not cost efficient. It was a fun idea to think
about though!

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tinco
It's an interesting idea. It seems a little crazy to go through the extremely
energy intensive process of electrolysis just to create a gas, but you could
recapture the gas and use it for something.

There's got to be a catch though. I think it's going to be that gas is too
light to effectively move a turbine so the amount generated will be really
small (i.e. smaller than the electrolysis costs)

~~~
stephengillie
Yeah, we've got to expect the 2nd Law of Thermodynamics to come in and ruin
the party.

You could power the electrolysis from solar, but then you've got transmission
loss on the wires. You're right the gases are too lightweight to push more
than the lightest fan turbine.

Even having the gases get separated, turn a turbine while floating up, get
recombined into water, then be pulled down past another turbine by gravity, we
might not get the full 1.5v back.

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pjc50
Look, bare hydrogen from electrolysis is not magic and not that useful.
Hydrogen is a pain to store.

What it _is_ useful for is as input to the Sabatier reaction, where it can be
combined with CO2 (if you can extract it from the atmosphere without expending
too much energy) to produce methane. Which can be stored or turned futher into
gasoline, jet fuel, etc.

Or you could just use free Canadian propane:
[http://www.argusmedia.com/pages/NewsBody.aspx?id=1041736&men...](http://www.argusmedia.com/pages/NewsBody.aspx?id=1041736&menu=yes)
or any of the natural gas being flared at the moment because it's too cheap.

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endymi0n
Pretty misleading article, mostly linkbait - the catalyst doesn't actually
_split_ the water, it's merely holding up to the _electricity_ splitting the
water better than other low-cost alternatives before. The principle and its
disadvantages aren't different to William Nicholson in 1800. Electricity isn't
for free. Hydrogen is hard to store and transport. Nothing new to see - move
on.

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kbenson
> Hydrogen is hard to store and transport.

If only there was a stable medium in which it could be transported, and an
efficient way to extract it from that medium at a destination where it could
be used...

I think perhaps your focus is a little narrow.

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ksenzee
No, water really isn't fuel storage. If you're at the destination where you
want to use hydrogen for fuel, and you also have at your destination the
electricity needed to split it, you can just use the electricity. No need to
turn it into hydrogen and then burn the hydrogen.

~~~
kbenson
Except if you need a form of energy that you can distributed at a location,
have abundant electricity and water at a specific point at that location, and
don't have infrastructure to efficiently move electricity around. But yeah,
transporting water itself probably isn't smart.

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sappwaste
Don't accidentally drop it in the ocean

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stephengillie
It _would_ free up more O2 and increase the amount of oxygen in the
atmosphere. Eventually.

What would that do to greenhouse gases and global warming?If we converted (for
example) 1% of the ocean to hydrogen, oxygen, salts, etc. Would air pressure
increase? Or would the atmosphere simply expand?

Edit: Since everyone's confused about how I'd power it, I'd use solar power.
Solar panels can easily output 1.5v today.

~~~
JshWright
This process still requires electricity to pass between the anode and cathode.
It doesn't just magically split water.

To address your hypothetical though... Both would happen. Air pressure is just
the weight of the atmosphere above you. If you add more gas to the atmosphere,
it would indeed get 'bigger', and would therefore weigh more, resulting in
higher air pressure.

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stephengillie
Yes, this process requires so little electricity that it can be powered by
scrap solar panels. I've got 2 at home that provide 1.5v each. TFA hasn't
provided other details, such as required amperage.

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ars
> Yes, this process requires so little electricity that it can be powered by
> scrap solar panels.

What?? The amount of hydrogen released is equal to 82% of the electricity
input. Why are you saying "so little electricity"? If you have "so little
electricity" you also have "so little hydrogen".

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stephengillie
The process, as described, used 1.5v. That can be produced by a common solar
panel. Thus we can scale it. And spread it across a small amount of time.

Did you and everyone think I was proposing to use gigawatts and electrolyse 1%
of ocean water in a few seconds? O_o

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ars
You can produce 100,000v by a common solar panel as well if you want. Voltage
is completely irrelevant, what counts is energy.

> Thus we can scale it.

I don't follow. What does voltage have to do with anything?

> Did you and everyone think I was proposing to use gigawatts and electrolyse
> 1% of ocean water in a few seconds? O_o

Um, yes. Do you have the slightest idea how much energy it would take to
electrolyze 1% of the ocean? I did some math for you: you need 1.752×10^26
joules. If you had a gigawatt available to you it would take 5,552,000,000
years.

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stephengillie
I thought voltage, at a certain amperage, was a way of describing energy.
Sorry for my confusion.

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ars
You're not wrong, voltage times amperage does describe the energy, but voltage
alone means very little.

In this case energy is what counts not voltage.

