'Major discovery' from MIT primed to unleash solar revolution
web.mit.edu
web.mit.edu
I fell like I'm missing a joke somewhere.
First off: what does electrolysis have to do with photosynthesis? If you want to store energy it's just as important with wind, or any other.
Second: photosynthesis and photovoltaics are not the same thing. They seem to confuse them quite a bit. And on top of that, this seems to have nothing to do with either of them - it's all about electrolysis.
Third: "Currently available electrolyzers, which split water with electricity and are often used industrially, are not suited for artificial photosynthesis because they are very expensive and require a highly basic (non-benign) environment that has little to do with the conditions under which photosynthesis operates."
Has so many errors I don't even know where to start.
a: electrolysis does not require a basic environment, it requires a salty one.
b: again mixing up photosynthesis and photovoltaics
c: there is no such a thing as artificial photosynthesis. Only plants know how to make hydrocarbons from water CO2 and light.
If someone actually did manage to create artificial photosynthesis that would be massive. Which is what I hoped to read about here, and then I didn't.
Fourth: they start off saying something about advances in solar power, and well? Where was the advance? All I see is something about electrolysis.
Fifth: "[plants] storing energy for use when the sun doesn't shine." Most plants don't actually do that. They don't store energy, they make hydrocarbons, which are not an energy source for them, they are the final product. (For us the hydrocarbon is energy storage.) There is the CAM photosynthesis cycle used by pineapples, which does actually store energy for later. But the only reason the pineapple does that is so that it doesn't dry out during the hot day, so rather it collects it's CO2 at night. This does not seem to apply here.
Someone: please tell me if I missed something massive, but this really looks like the kind of nonsense energy inventions you read about all the time. But, but, but it's on mit.edu!
The paper does focus on photosynthesis, however, because the Nocera's lab works on "artificial photosynthesis," a field largely devoted to understanding the electrochemical processes of photosynthesis and mimicking them in man-made systems. For the most part, "artificial photosynthesis" focuses not on carbon fixation but on the transformation of light to electrochemical energy (via electron/proton transfer). This is the process that Nocera's research is replicating, and likely why he focuses on using solar cells as the source of energy, to parallel a plant's use of solar energy as a route to energy storage/O2 production.
Finally, I think some of your scientific analysis needs correction:
Electrolysis (in its simplest form) doesn't require any solute - it can be performed, very slowly, in pure water. Adding salt (say, NaCl), as you mention, speeds up the rate greatly. However, in doing so, the reaction changes - you'll evolve hydrogen as before, but at the anode you'll evolve chlorine gas, not oxygen. You can't use electrolysis alone to produce oxygen gas or as a route to storing energy. One alternative to this is to use an electrocatalyst, but currently, (as the article mentions), the only available catalysts require expensive metals or very basic environments (or both). This article is on the discovery of a new catalyst that will allow for the production of oxygen via catalyzed electrolysis at neutral pH and with a cheap, abundant catalyst (cobalt).
Also, if we're looking at the same quote: "storing energy for use when the sun doesn't shine," the article is talking about humans storing energy, not plants. Even so, plants do store energy for when the sun doesn't shine. They metabolize hydrocarbons into ATP via mitochondria, just like we do - so glucose and other products of photosynthesis are indeed forms of stored energy.
I think a lot of the confusion stems from the fact that we're reading a popular article and not the actual research - these articles tend to pick up on terms like artificial photosynthesis, energy production, and solar energy and run with them.
>artificial photosynthesis" focuses not on carbon fixation but on the transformation of light to electrochemical energy (via electron/proton transfer).
Then why call it photosynthesis? It's not, it's photovoltaics. If you want photosynthesis you have have to fix carbon, or you're making a mockery of the term. And if you are making hydrogen directly, then call it photolysing.
Either way you are not synthesizing anything.
I didn't realize that chlorine is preferred to O2, but what does it matter? I don't want O2, I want H2, and once all the chlorine is gone, won't the sodium hydroxide work just as well as NaCl? Or is that what you mean by 'very basic environment'?
They should rewrite that article and omit any mention of solar, just say they invented a new cheaper way to electrolyze water. Applications include storing energy from solar or wind for when the sun isn't shining.
Doesn't the above paragraph make a lot more sense than the parent article?
I was wrong about the chlorine production, actually - it only occurs at high concentrations of salt. Otherwise (or with different solutes), you can produce oxygen. Still, I believe that this reaction is not efficient enough to be feasible as an energy source. Overall, you do want the hydrogen, but you also need an oxidant to, for example, run a fuel cell. I think there are hydrogen-chlorine fuel cells, but I imagine it would be easier and more practical to run a hydrogen-oxygen cell instead to avoid using chlorine gas/producing HCl. In any case, it boils down to developing catalysts to improve the rate and efficiency of this electrolysis (by lowering overpotentials).
I agree with you that your paragraph makes a lot more sense than the parent article. It's annoying how these press releases make things seem much more revolutionary than they really are.
The reference to photosynthesis is indirect. I think the point of the reference is that photosynthesis stores the sun's energy and then uses it later on. And that is what his process will allow. Photovoltaics can provide energy all day, and instead of feeding the grid and getting energy credit the system can create hydrogen and oxygen gas and then use those later on when the sun is no longer out (through a fuel cell for example). The process, he is claiming will only presumably require water and some other "common" materials.
I imagine something like this could be possible. Some unanswered questions: How efficient is it, if it isn't efficient then can it scale? How expensive are the materials required? Where are the details? A paper, article in a magazine or even a web site with details. I have no idea why MIT would announce something like this without publishing first or simultaneously.
Links I could find:
http://web.mit.edu/chemistry/dgn/www/research/e_conversion.h...
Unfortunately, there's no mention of a publication for this discovery, but you can read about their pior work on their webpage: http://web.mit.edu/chemistry/dgn/www/
I know what you're saying and had similar thoughts. I suppressed my concerns thinking "some of this seems wrong but this is on mit.edu so they must have been through many checks".
Same lesson to be learnt as http://news.ycombinator.com/item?id=263599 ?
In short: as far as I can tell this invention is a new catalyst for increasing the efficiency of electrolysis.
But the catalyst is not better than current ones, it's just less toxic (and therefor cheaper). Which, while helpful, is far from groundbreaking.
The electricity can come from anywhere. Saying solar is just a buzzword to get people to click.
If not more efficient, is it at least a cheaper form of energy storage? (Platinum in the catalyst suggests no, although a very thin layer might be good enough.)
I'm not sure what you mean by whether it's more efficient than charging and discharging a battery. But the lifespan of a fuel cell is potentially indefinite and it does not require recharge(add in Oxygen and H+ any time and electricity starts to flow). Further, with each battery cycle, the efficiency of a dry cell decreases.
I think this electrolysis process can definitely make a cheaper form of energy storage than, say, batteries. Even though each anode requires small amount of Platinum, but considering the long lifespan of fuel cell storage, this form of energy storage costs much less than traditional batteries in the long run (all the toxic disposal!) And even for the purposes of propulsion, fuel cell discharge is much more efficient than internal combustion engines.
This particular article, on the other hand, makes no mention of the economic factors involved in the said processes. To top it off, there's been a sway of "amazing solar discoveries" recently and we'd be lucky to see a handful of them actually make it into the real world. That said, I'll believe it when I see it.
Requiring nothing but abundant, non-toxic natural materials, this discovery could unlock the most potent, carbon-free energy source of all: the sun. </quote>
Now we can split the water (H2 + O2) in a cheap efficient and highly manufacturing way </quote> http://www.sciencemag.org/cgi/content/full/sci;1162018/DC2
Though It requires Platinum at the moment (Pt is not a cheap earth-abundant material).
However, indeed nothing is said on the efficiency of the whole process and thus the economics of this process. How large a system do you need for a household and what would it cost? Hopefully we will get answers soon.
Still you need photovoltaic cells or windmills to produce electricity for your house, your car, etc. And you need extra electricity to produce H2 and O2 for times when there is no sun or wind. PV cells still cost a lot and still are not efficient enough (thus take up too much space). So, there are still other missing links to solve to really start a electricity revolution.
If you could reduce the amount of energy required to electrolyze water, then it would make an extremely good energy storage vehicle. That's exactly what this research is about.
It's great to try to make it more efficient, but this research doesn't actually do that, it just makes the equipment cheaper, but at the same efficiency.
And besides electrolysis is a terrible way to store energy because storing hydrogen is impractical (it leaks right though metal). Plus there are unavoidable inefficiencies.
To balance the load and maximize revenue, a number of power producers employ a decidedly low-tech way to store energy: every night, they pump a lake of water up a mountain, and during the day they drain it through hydroelectric generators.
Really! I shit you not: http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
Also, storing large quantities of (I assume pressurized) gas has got to be expensive. The nice thing about liquids is that you can store them in a vat, or a dammed up canyon.
I didn't rtfa, its probably cool tech, but hardly a revolution. Good luck guys.
Even th article seems to focus on how they invented non-toxic catalysts. It mentions nothing about improving the efficiency of the reaction.
Not sure what the platinum has to do with it though.
Platinum is often used in catalysts. It works by providing an alternative reaction pathway that takes less energy to fuel the reaction. An analogy is that instead of rolling a rock up a hill to get it from point A to point B, the catalyst provides access to a tunnel through the hill.
The same is true with current processes, if your catalyst is being used up to bind oxygen then a: it's not a catalyst it's a reactant, and b: well don't, and c: you're not electrolyzing water, you're doing some more complicated reaction.
So emitting O2 from electrolysis is not even the slightest bit new. That part of the article was basically nonsense.