Single-catalyst water splitter produces clean-burning hydrogen 24/7(news.stanford.edu) |
Single-catalyst water splitter produces clean-burning hydrogen 24/7(news.stanford.edu) |
True, because it's hard to make materials that will hold it. It tends to damage metal and leak through other things.
> and you basically have a fuel-air bomb on your hand if anything goes wrong with your tank.
No you do not, there is no air in your tank. Hydrogen is much safer than gasoline, if released it rises up in the air almost instantly. So a hydrogen fire would put itself out pretty quickly, and would not burn much that is around it.
That's burying the lede a bit surely? If this process could actually be cheaper than nat. gas power plants as a backup for solar or wind grid electricity generation—or, of course, ideally if it could be cheaper than just forgetting about solar or wind and simply generating all that grid power using natural gas—then that would be big news, right? Any viable application to transport would just be icing on the cake.
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...
If you have the power source at the point of use, it's still more efficient to just use that for propulsion.
There has to be a way to store the hydrogen for later use.
I'm reminded of the "run your car on water/save fuel" scams which involved "HHO generators"
I used to work with a guy who was convinced that his HHO generator would yield all kinds of increased fuel efficiency on his gas guzzling pickup truck.
He didn't have the background to understand why it's not possible to get more energy out of burning the brown's gas than he used to create it.
While increased efficiency in the splitting of water molecules is a great thing, there's still basic thermodynamics.
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?
You need electricity at the point of use, which is mobile for a motor vehicle. If you have mobile electricity, using it to get hydrogen out of water, so you can run your hydrogen powered generator to get electricity doesn't make a lot of sense.
Hu? Why? You have electricity, you use it to make hydrogen, then burn the hydrogen and power something?
Why not just use the electricity directly?
Edit: I guess they mean they are producing enough hydrogen that they could burn that hydrogen (recombine it with water) to generate a constant 1.2v of electricity.
Also, what amperage is required for this to work?
The main issue is how much energy are you putting in to get how much hydrogen gas. That hydrogen gas can be used to power a fuel cell (for example) which generates electricity.
Historically, the amount of electricity you get out of that conversion cycle (through the production of hydrogen gas) isn't great (don't have numbers in front of me). If they're improving that ratio, that is good news. If they're doing it with a cheap and durable catalyst, that's even better news.
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?
Considering that these are extremely common metals, I can't see why this wouldn't be viable, even with anode/cathode degradation.
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?)
This is something I'd forgotten about this process - use energy to separate hydrogen and water, then recombine later to release the energy. And the waste product from this is the water used to start the process (and the energy and heat lost to entropy). Very clean!
Oxygenating atmospheres is easy (and obviously dangerous if you get high partial pressures), the issue is generally scrubbing CO2 out.
Earth air is mostly a mixture of 72% nitrogen, 24% oxygen, 6% carbon dioxide, and other stuff. Could humans breathe if they were in an environment that was 78% carbon dioxide and 24% oxygen? (IANADoctor)
Unless - you have a nuclear powered device which melts trapped CO2 ice and then generates O2?
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.
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!
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)
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.
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... or any of the natural gas being flared at the moment because it's too cheap.
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.
Edit: You could not possibly be talking about water, could you?
How exactly were you planning on extracting the hydrogen from the water?
No, there's no way you were talking about water, that would be far too stupid. So please tell me what medium you meant.
It's not magic.
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.
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.
It's powered by electricity. Where are you getting that electricity from?
If you add enough oxygen and keep adding oxygen, eventually everything is on fire.
> If you add enough oxygen, and keep adding oxygen, then eventually you'd get enough to breathe?
Nope. As the sibling comment noted, around 1% CO2 will start making people uncomfortable and stuffy (the human body is not sensitive to lack of oxygen so much as excess of CO2, that's why e.g. nitrogen suicide is almost painless), and concentrations above 7% CO2 start being lethal regardless of oxygen presence.
But CO2 has significant effects long before that, studies have shown decreased cognitive abilities starting at ~0.1% CO2.
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.
That said energy in different mediums does have different useful properties, and while transporting water may not be too bright, the fact that it's fairly ubiquitous at many locations, and while hydrogen may be hard to store and transport, I believe in some instances it's easier to transport than electricity when there's no infrastructure in place.
I interpreted the top level comment's stance as this is a non-story because converting water to hydrogen is worthless (or at least it's worth hasn't changed). I still reject that stance, as I think efficient conversion between mediums may open possibilities that we previously discounted, so may be strategically useful.
So this has value only in that you can store the hydrogen or use it somehow. You can also store electricity, so they question boils down to: Which is easier to store: Hydrogen or Electricity?
Water simply never enters into the question.
Storing hydrogen is hard enough that it's pointless to even talk about. Storing electricity can only be done in small quantities.
That's why I said methane: The best thing to do is grab some carbon and make methane with your hydrogen, methane you can store.
This is not really a solution for anything though, round trip efficiency of solar cell->electricity->hydrogen->methane->electricity would be quite low.
Much better is heat+coal+water = methane (you can thermalize water with heat). You can use a solar collector or nuclear power.
https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...
Yes, this is a thought experiment.
Were you seriously concerned that I had a solution for rising ocean levels?
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".
Did you and everyone think I was proposing to use gigawatts and electrolyse 1% of ocean water in a few seconds? O_o
If you actually did this you would increase the atmosphere to 10 times it's current size - and most of that would be oxygen, unlike the current mostly nitrogen. Most of which would probably escape to space.
You'd have to find something to do with the hydrogen though, if you released it it would just recombine with the oxygen and make water again.
> 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.
In this case energy is what counts not voltage.