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Alloy Could Produce Hydrogen Fuel Using Sunlight
intellitech writes "Using state-of-the-art theoretical computations, a University of Kentucky-University of Louisville team demonstrated that an alloy formed by a 2 percent substitution of antimony (Sb) in gallium nitride (GaN) has the right electrical properties to enable solar light energy to split water molecules into hydrogen and oxygen, a process known as photoelectrochemical (PEC) water splitting. When the alloy is immersed in water and exposed to sunlight, the chemical bond between the hydrogen and oxygen molecules in water is broken (abstract). Because pure hydrogen gas is not found in free abundance on Earth, it must be manufactured by unlocking it from other compounds. Thus, hydrogen is not considered an energy source, but rather an 'energy carrier.' Currently, it takes a large amount of electricity to generate hydrogen by water splitting. As a consequence, most of the hydrogen manufactured today is derived from non-renewable sources such as coal and natural gas. The team says the GaN-Sb alloy has the potential to convert solar energy into an economical, carbon-free source for hydrogen."
Do you care about your fellow man who was born with less privilege than you? Then work hard to make stories like this into a reality so that every poor family can have the access to cheap energy to heat their homes and to power the car in their driveway.
That's a better story than lowering the standard of living for everyone. I'd rather use technology to raise everyone up, even if it is only to the modest levels that you and I take for granted.
We've used solar power to split water into hydrogen for decades, what matters is cost. How does this compare with standard solar splitting based on surface area? Do you need a crystalline structure to work? Given that raw silicon is more common and more used I expect it's much cheaper. The article talks about semiconductors so it probably needs a crystal structure (drives up cost), so even with better efficiency (single step vs multi step splitting) it's still probably more costly.
How many of these are going anywhere years later?
Most aren't. Some are. That's pretty much the way R&D works: most projects fail, but the ones that succeed change our lives, generally for the better. If you're not interested in hearing about the early stages, when success or failure is impossible to predict, that's fine; no one's making you read those stories.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Having solar panels on your roof that can power your stuff -and- refuel your car is a better investment than a solar plant for each.
Imagine you're stuck in the desert with a bottle of water... you have to take a pick whether you drink your water or pour it in your car
Easy answer really. Drink your water and pee on your car.
ChE here. I read the article (hooray for university journal access), and I know exactly why there's so much hedging: this is a purely computational, DFT paper, with no experimental results to back it up. In the academic world this is not particularly uncommon, and DFT studies are an amazingly powerful tool to identify (potentially) optimal material combinations that would take researchers centuries to discover by systematic experimentation. But that's just it: "potentially". DFT often (necessarily) overlooks potential external effects that only occur in real systems. Somebody higher up really jumped the gun by making a full press release on a typical journal article in the photocatalysis field.
Gallium nitride (GaN) is used to make blue LED chips, typically vacuum deposited on top of sapphire wafers. While it is a very good semiconductor, it is an order of magnitude more expensive than silicon wafers. Unless there is a huge breakthrough in mass manufacturing cheap GaN wafers, it will be much cheaper to use silicon solar cells to generate electricity and electrolyze water with it.
Does the paper talk about the efficiency of this solution vs Photovoltaic panels and electrolysis? If the hydrogen and oxygen would be split over a large area (say a roof or larger), how would the gasses be collected? It sounds like an interesting result, but not so practical in application...
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Wanted: monovalent to occupy vacant orbital. It's a quad, but the other three spots are spoken for. If you are an H, we'll be an alkane. If you're a hydroxyl, we'll be an alcohol.
Obi-Wan: "I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were sudden
Why, particularly? I would guess that which one would be "better" would be a calculation that combines ease of access, cost, aesthetics, and ROI. Often, operations done at large scale can be done more efficiently than in a distributed fashion. Other times, the cost of distribution can offset this interent efficiency.
We don't yet know which one is "better" - the market is still merging.
One area that I'd personally love to see more solar panels is over parking lots. Nothing quite beats the misery of walking out of a nice, 75 degree mall into the blistering, 100-degree heat in the summer time, only to sit down in your 160 degree car, cursing and swearing at all that damned free energy the sun packed into your car.
But cover that parking lot with a lattice of solar panels so I'm getting into a merely hot 95 degree car while all that energy is used to power the A/C at the mall I just got out of, that would be swell.
I have no problem with your religion until you decide it's reason to deprive others of the truth.
2 weeks ago this same source reported on research at the PNWNL that uses a Nickel catalyst for a 1000x improvement over the platinum catalyst process now used, for example, on the ISS.
Nothing quite beats the misery of walking out of a nice, 23 degree mall into the blistering, 37 degree heat in the summer time, only to sit down in your 71 degree car, cursing and swearing at all that damned free energy the sun packed into your car.
Fixed that for you. Now stop using those damn Fred Flintstone units!
Circumcision is child abuse.
It uses gallium, which also makes great solar cells, more efficient than anything else. But the cost of gallium solar cells is so high that they're only used on spacecraft. They're about 3x more efficient than silicon solar cells, and 300x more expensive.
Exactly as much energy as you get back by complete combustion of the octane, divided by the efficiency of the conversion. See 'Fischer-Tropsch' process.
This is basically what you do if you want oil and you don't want go to Mother Nature's Giant One-Time Only Sale (All coal and oil accumulated over the last 500000000 years is old inventory and must go now! This is a one-time offer, bound to end within 200 years of starting! Don't miss out! Extra discounts available for first 50% of supply, for details please inquire within. No warranty is implied; Buyer takes full responsibility for any mass extinctions, polar meltdowns, or disastrous climactic shifts resulting from use of product. No returns accepted, all sales are final.).
People's rooftops could be used as well. I heard of a program somewhere where they pay you a monthly rate to put energy back into the grid from solar panels placed on your roof. Requires a capital investment, though, which you earn back over the years (20 years IIRC). So unfortunately longer than the majority of people stay in one house.
There are companies here in the UK that do that (essentially you are renting your roof area to someone for them to put their panels on, and in payment they give you a cut of the money they make). It seems like a good idea to me because most individuals can't afford a long term investment like PV (which costs thousands of pounds and takes 10-20 years to break even). Unfortunately I've also heard that this is incompatible with most mortgages, so until those kind of problems can be fixed it isn't going to be very wide-spread. Here's an idea - how about the mortgage lender offering to shove PV panels on your roof as part-payment for your mortgage?
http://blog.nexusuk.org
Nothing quite beats the misery of walking out of a nice, 296 Kelvin mall into the blistering, 310 Kelvin heat in the summer time, only to sit down in your 344 Kelvin car, cursing and swearing at all that damned free energy the sun packed into your car.
Fixed that for you. It's 21st century already.