New Hydrogen Fuel Catalyst Discovered
Hydrogen (H) fuel cell technology could perhaps become the cleanest form of energy, both in terms of generating the gas and in terms of combustion products (which are just heat and water). The biggest problem has been making the process of H generation clean, efficient, and cheap, as the current, main source of H gas is coal.
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But H gas can also be derived more efficiently and ecologically from the splitting of water (H2O) molecules. But here too, there is one major obstacle: the controlled (non electrical power using) process of hydrolysis (water splitting) requires a catalyst to get the reaction going. Currently, the most efficient catalyst for this is the heavy metal element Platinum. Platinum works great, except that it is a rare metal, and very expensive to mine, thus making it impractical for mass industrial usage.
In addition, hydrolysis requires two separate catalytic steps–the first (the + anode) strips away electrons from the hydrogen atoms in the water and then combines the freed Oxygen (O) atoms into molecular oxygen (02). The second step (the - cathode) allows the positively charged H atoms to acquire electrons and thus pair up into molecular hydrogen (H2). The H2 gas is then combusted (via the O2) to power the vehicle, leaving only water (and some heat) as exhaust. To make this all work cost-effectively, cleanly, and without altering the ph level of the water (which would interfere with catalysis), finding a suitable catalytic agent or agents has been the over-riding concern with fuel cell engineers
Recently, researchers at the Massachusetts Institute of Technology (MIT) reported discovery of a new, water-splitting catalyst that is far more environmentally friendly than Platinum: it’s a composite of Cobalt and Phosphorus, which are relatively inexpensive and plentiful elements. This is a “giant leap” in hydrogen fuel technology and it has many energy scientists excited and cheering.
As with every major breakthrough, the technology needs much improvement. The catalyzing system works by taking an anode made of Indium Tin Oxide (ITO) and sinking it into a solution of cobalt ions (Co4+) and potassium phosphate (KP). But this system still requires an external jolt of energy to kick in the water-splitting reaction (this energy source does not come from the stored fuel energy and is not recovered in the process). Also, the catalyst can only deal with low levels of electrical current. But researchers are still optimistic about progress with this newest approach, especially since the new catalysts are so easy to make.
On other major engineering challenge is to connect the electrodes in the cell to solar panels (that supply the external jolt to the catalytic system) to provide a clean source of energy input. Further, it needs to be shown that the catalysts can work in seawater (which is high salt/alkaline). Seawater is a cheaper and more abundant water source, and if a workable system could be devised, such a system would be able to generate H, transport it to storage cells on shore, and convert it to electricity and (fresh) water. This goes beyond merely providing a fuel source for automobiles; it could satisfy two of civilization’s most basic needs–clean, plentiful energy and clean, drinking water.
Image credit: simple H Fuel Cell diagram courtesy of the IOWA Dept. of Natural Resources
I don’t know where you’re getting your information, but there are more than a few technical errors inyour article.
1. Most hydrogen is produced by steam reforming natural gas, not from coal
2. Dr. Nocera’s invention, while interesting, does not change the thermodynamic fact that in order to split water into hydrogen and oxygen by electrolysis you need to supply an amount of electricity equal to the amount of energy that is produced when you burn hydrogen or otherwise combine it with oxygen. if you could do it for less energy you would have the chemical equivalent of a perpetual motion machine.
3. Neither water electrolysis or fuel cell operation can be 100% efficient no matter what kind of catalyst you use. This is because in electrolysis some of your energy goes to overcoming the electrical resistance of water and is lost as waste heat. PEM fuel cells, the most popular type for automotive applications, also lose a lot of energy as heat and are only 40% efficient in generating electricity from hydrogen. The most efficient electrolysers now on the market are made by Statoil. They are about 84% efficient, a figure that is close to the maximum possible. http://www.electrolysers.com/
4. The thought expressed by Dr Nocera tht a homeowner with a solar cell array could set up a water electrolysis unit and a fuel cell, using the generated hydrogen as a means of storage is only slightly short of insane. Because hydrogen is so light it must be compressed to high pressure for economical storage. Hydrogen compressors are very expensive. Fuel cells are also very expensive and require periodic repalacement of the membrane, the most expensive part, because air pollutants poison the catalyst. Hydrogen is an explosive gas with no warning properties and, because the molecule is so small, tends to leak through gaskets fittings etc. you could turn your garage into the Hindenburg.
5. There’s a much simpler and cheaper method of storing the output of your solar cells. It’s called net metering. You make your electric meter run backwards by putting your excess generated power into the grid. when the sun isn’t shining you use utility power. The equipment is dead cheap and most utilities allow it. I have a neighbor who does it and his net electric bill runs less than $100 per year.
If you have any questions, drop me a line
I think the tendency/need to point out errors in something makes a person prone to distortion.
The fact that the blog post condenses information, or abbreviates a technical description, does not equal “numerous errors”.
I get my information from, amongst other sources, Science magazine–one of the top two most respected and peer reviewed journals in the world.
First: my citing of coal as the main source of free hydrogen was perhaps inaccurate–I should have said hydrocarbon fuel sources (coal being the least “pure”, or dirtiest, as it also has a good deal of sulfur in its ore form).
Secondly, the blog post plainly states that the catalyst isn’t perfect, and that the catalytic system still requires an external jolt of power (periodically) to get the reaction started (and the energy is not recovered in the process), thus it is not, nor is it implied to be, a perpetual motion machine (this is similar to plasma gasification systems which, through combustion of garbage with plasma jets, generate huge amounts of energy, some of which is used to power the gasification system. But the system needs a periodic jolt of external electricity to keep the whole thing (i.e., the super hot plasma jets) going. Nothing in the blog post (simplified as it was) implies perpetual motion (”free lunch”) or energy generation.
Nowhere do I state or imply that the system is 100% efficient. it is, at base, an alternative to burning fossil fuels (and drilling for oil/natural gas)
Your statement “in order to split water into hydrogen and oxygen by electrolysis you need to supply an amount of electricity equal to the amount of energy that is produced when you burn hydrogen or otherwise combine it with oxygen. If you could do it for less energy you would have the chemical equivalent of a perpetual motion machine.” is misleading, if not overly simplified. That is the point of a catalyst. A catalyst gets a reaction started without itself being changed in the process (or very little compared to the primary reaction agents). A tiny amount of a catalyst is sufficient to get an energetic reaction going. In organic chemistry, enzymes play this catalytic role (by grabbing valence electrons). But the amount of energy used to make an enzyme is far less than the amount of energy released when that enzyme breaks up, say, an ATP molecule (of course, ATP has to be manufactured, and in this example, is congruent to the water molecule). Remember that the catalytic system generates molecular forms of H and O (H2 and O2) which have more total energy that just H and O. And since (in the idealized example) the source of this H and O is seawater, there is a nearly endless supply (the total system is not closed, or at equilibrium); there is constant input of material, and a periodic energy input.
But of course, the Second Law holds (for “closed” systems at/near equilibrium); there is indeed heat loss, and so, even highly efficient catalytic systems require occasional “refreshment” (replacement of the catalyst) and jolts to keep them going (and keep the system away from equilibrium, where entropy abides).
To use a slightly different example, a hydrogen bomb certainly produces vastly more energy than the amount of energy used to bombard the nucleus and set off (catalyze) the “run away chain reaction” (the system is pushed far from equilibrium), which is the explosion (the energy output).
Regarding your 4th point: these are all engineering problems; no one ever said that hydrogen was a hundred percent safe–it’s about bang for your buck, so to speak. And the blog post doesn’t suggest turning your garage into a hydrogen storage facility. It took the space program 20 or so years to perfect the liquid oxygen fuel systems that eventually carried us to the moon. Again: an engineering problem.
Regarding you last point: that’s a great idea (and I was already familiar with it)…why didn’t you just come out and say you are promoting personal solar energy generation? This post was about Hydrogen fuel cell technology, and while not as “clean” as solar, we must not forget the industrial process that creates photo-voltaics: PV cells utilize rare metals (gold in some cases) and also silica, which is far from “clean” (it causes lung damage). Now, next generation solar power cells are using amorphous crystals, organic films, and solar condensers (further examples of engineering problems surmounted).
Michael-
Your rebuttal seems a little muddled.
The thermodynamics are as Ed describes. Combining oxygen and hydrogen to produce water is ‘downhill’ so energy is released. That is to say, water is lower in energy than oxygen and hydrogen. To separate them, you have to add energy. At minimum, the amount of energy would be what you get by burning them.
The catalyst doesn’t alter the energy difference between the reactants and products. It lessens the ‘activation energy’ needed to get a reaction to proceed. The very best it can do is minimize this energy. At zero activation energy, you still have to put in energy to separate water.
Suggesting that somehow the catalyst needs a “periodic jolt” of energy is not accurate. A perfect catalyst will not alter the fact that it requires energy to split water. It always, and everywhere, requires energy to split water.
The activation barrier is there in the reverse reaction as well, despite the fact that ultimately the reaction will liberate energy. The stored hydrogen and oxygen won’t recombine at a meaningful rate without another catalyst. Generally this is Pt, or worse, an expensive alloy of Pt.
I think the work is interesting, but I am not sure what the hype is about.
Michael, you said:
“That is the point of a catalyst. A catalyst gets a reaction started without itself being changed in the process (or very little compared to the primary reaction agents). A tiny amount of a catalyst is sufficient to get an energetic reaction going. In organic chemistry, enzymes play this catalytic role (by grabbing valence electrons). But the amount of energy used to make an enzyme is far less than the amount of energy released when that enzyme breaks up, say, an ATP molecule (of course, ATP has to be manufactured, and in this example, is congruent to the water molecule). Remember that the catalytic system generates molecular forms of H and O (H2 and O2) which have more total energy that just H and O. And since (in the idealized example) the source of this H and O is seawater, there is a nearly endless supply (the total system is not closed, or at equilibrium); there is constant input of material, and a periodic energy input”
The total amount of chemical and thermodynamic ignorance exhibited in just that one paragraph is staggering.
Here are some hard facts about H2O electrolysis. It is energetically UNFAVORABLE. That means that you must always put more energy in to achieve the electrolysis of H2O to H2 and O2 than you can ever recover when you recombine the two. The catalysts you speak of can reduce this inefficiency, but they can never eliminate it. The bottom line is that there is no chemical energy available to be obtained from splitting water, never has been and never will be
(unlike ATP, which happily supplies a nice “kick” when that 3rd phosphate splits off with or without a catalyst). I’ll refrain from ripping your “comparison” of nuclear fusion with the simple electrolysis of water (your exact words were “To use a slightly different example.” “slightly”, heh.)
Son, get yourself to the nearest junior college and enroll in a freshman chem course followed quickly with a stint in sophomore physics. Unless you are one of those who believe that learning how the natural world actually works somehow “stunts” the mind and leaves you unable to engage in “creative” thinking.
Sorry to be so harsh, but I am tired of seeing wishful thinking dressed up as real scientific fact.
For one thing, Michael does not claim a reduction in energy used to make H, he simply points out a more cost-effective way to do it. Everyone here view the H conversion quation upside-down: If we all agree that hydrogen creation takes more energy than it produces, we look at the process as more of a distribution question. If H production is the equivalent of conventional electrical power generation and transmission, then we’ll treat H as a working storage medium, rather than an end result. Then we accept the <100% conversion losses as the normal and cost of operating in our entropy-ridden universe. The wisdom here is seeing hydrogen as portable energy, gotten through a loss-governed conversion process, one that makes financial sense when clean electricity is cheap enough to “convert” to H.
When H becomes a working gas that transported and used in the same way as natural gas, then storage is no longer a problem; you use it when and where needed. When the US or other developed nation makes the switch to H as the mainstream gaseous fuel, then the infrastructure is the storage system and individual, even residential H producers can utilize things like net metering. When users need either transportation fuel or electrons, they use the H system. Try that with natural gas!
H is the perfect medium to add to a world where distributed generation and use deprives multinationals and hostile countries of their monopoly power. It also deprives governments of freedom-limiting central energy planning. If a system of coastal wave, interior wind and solar, biofuels and other technologies provide the electrons, then the main focus of energy policy becomes practical storage and use. I understand that it takes time to adjust our mental model, but dismissing these new ideas makes me think that Michael’s critics are driven by their own self interests.
Bruce/David
Thank you for your comments. First, responding to David’s comments:
This happens fairly often on blog posts–people do not read carefully enough; they pick up on one or two things (that they see as wrong or simplified) and go for the critique, seldom rereading the original piece that brought on the critique.
If the amount of “thermodynamic ignorance” in my statement is “staggering”, and if my information comes from Science Magazine (describing the work of Dr. Nocera), then, unless my summarizing and interpretation of that information was totally wrong (and it wasn’t), then you are essentially saying that Dr. Nocera is staggeringly ignorant (thermodynamically speaking), and by extension, Science Magazine also, by publishing the (admittedly brief) article.
Secondly, it’s funny, I know of few other topics in Science that elicit so much confusion and argument as does Entropy and applications of thermodynamics (”heat death of the universe” etc.).
We should always bear in mind that entropy (heat death/loss of free energy) dominates for (closed) systems at equilibrium. Since there is nearly always another system external to the “framed” system from which to draw energy, we can, in theory, keep the system far from equilibrium, and “keep it going”, “defying” entropic forces (for a time). Even the cosmos can be viewed this way (as is, in fact, with some new “brane” based, cosmogenesis theories).
This is true for evolving, biological systems especially, which (according to the Second Law) should not be able to exist, yet do (as they maintain a constant energy flow keeping them away from equilibrium; they “export” entropy). And yes, I realize that I am discussing biological systems, and this is a physical system (but they are not that dissimilar, hence my use of enzymes and ATP as an analogy).
I admit that my nuclear argument was extreme (I was tired).
And while it has been awhile since physics class (admittedly, I was more interested in “wet” biology), I think you go over board in your critique (Are you a physicist? They tend to be the most arrogant when it comes to stating an opinion). In any event, it is helpful, before launching into an “entropy” ” attack, to define exactly the system that you are applying the Second Law to. This particular system is not closed (hence the perpetual motion argument is not even in the offering here), and since two of these systemic inputs are electricity (supplied externally; possibly by solar power condensers) and seawater (an “endless” resource)…and since at no point does the article assert that the fuel cell is “getting something for nothing”, vis avis hydrolysis…then, I’m not sure what the point is of your critique…except to assert some superior knowledge regarding physics (which is true as far as it goes, which is not far)…and that’s ok, too (but perhaps you should study up on your biology, which offers a more complex definition of the role of entropy in far-from-equilibrium systems, which fuel cell tech. seeks to emulate, in a sense)).
..just remember, there’s a forest beyond the trees.
Bruce: you said:
‘Suggesting that somehow the catalyst needs a “periodic jolt” of energy is not accurate. A perfect catalyst will not alter the fact that it requires energy to split water. It always, and everywhere, requires energy to split water.’
> Yes, I understand your point, and thanks for the clarification, but again, I do not anywhere say that the catalyst needs the jolt, but rather “the system”, meaning the total system. And this jolt comes from some external (to the system) source. This is clearly stated in the article.
I would love for your to explain what this “activation” energy actually is, or where it comes from (and where it goes). I don’t doubt your description, I just think that this is one of those explanatory words that needs its own explanation (definition).
Lastly, thanks HT Schmerdtz, for the cogent support.