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.
The good thing is that you get a lot of energy density this way. The bad thing is that hydrogen is difficult to store, and you basically have a fuel-air bomb on your hand if anything goes wrong with your tank.
> The bad thing is that hydrogen is difficult to store
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.
> 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.
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.
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...
With this efficiency, it could be feasible to just split the water at the point-of-use.
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.
> 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?
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.
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.
> With this efficiency, it could be feasible to just split the water 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.
I thought the 80% efficiency metric meant they were successfully converting 80% of the water into gas.
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.
Water is cheap, so converting X% of it to gas isn't the issue.
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.
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?
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.
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?)
Calling it a waste product here was mostly in jest. It's not every day that oxygen is the byproduct of a process, and not the goal itself.
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!
If you add enough oxygen, and keep adding oxygen, then eventually you'd get enough to breathe?
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)
> If you add enough oxygen, and keep adding oxygen, then eventually you'd get enough to breathe?
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.
Survive? No way. C02 concentration is between 0.036% and 0.041%. 1% would be uncomfortable and cause you to be drowsy. 7%~10% would lead to suffocation.
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.
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!
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)
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.
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.
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.
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...
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.
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.
Eh, you're right. Transporting water is stupid, I wasn't thinking that through very well.
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.
This converts electricity to hydrogen. There are very few situations where that is desirable - electricity is almost always more 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.
gravity+water meaning hydroelectric? We're kinda maxed out on that, plus if you wanted to store energy pumped water storage is better than methane (but there are not a lot of suitable sites).
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.
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.
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.
> 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".
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.
OK, in that case 1% of the ocean weighs 1.33×10^19 kilograms, the atmosphere weighs 5.1441×10^18 kilograms.
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.
>This bi-functional catalyst can split water continuously for more than a week with a steady input of just 1.5 volts of atomicity. That's an unprecedented water-splitting efficiency of 82 percent at room temperature.
