Hydrogen can be produced by means of electrolysis, i.e. running electricity through water in order to split it into its constituent hydrogen and oxygen. Current electrolyzers use a catalyst made of platinum. The same goes for fuel cells that recombine hydrogen with oxygen, in order to (re)produce electricity.
The problem is that platinum is a precious metal that costs about $1,700 to $2,000 per ounce, which until now made the equipment to produce and use hydrogen rather expensive.
Daniel Nocera and Matthew Kanan of the Massachusetts Institute of Technology (MIT) have discovered a cheaper way to produce hydrogen and oxygen from water. To produce oxygen, Nocera and Kanan added cobalt and phosphates to neutral water and then inserted a conductive-glass electrode. As soon as the researchers applied a current, a dark film began to form on the electrode from which tiny pockets of oxygen began to appear, eventually building into a stream of bubbles.
After analyzing the electrode, the researchers concluded that a cobalt-phosphate mixture, possibly combined with phosphate, had deposited as a film. Nocera and Kanan believe the film is the catalyst that helps break apart the water molecules to produce oxygen. The protons (hydrogen nuclei) released from the process pick up electrons and convert back into hydrogen at a partner electrode.
Nocera and Kanan also found evidence that the catalyst seems to refresh itself, a mechanism that would make maintenance of such oxygen-extracting systems far simpler than alternatives, although that finding needs confirmation from additional experiments.
The method works with nothing but abundant, non-toxic natural materials. Cobalt costs about $2.25 an ounce and phosphate costs about $.05 an ounce. "The new catalyst works at room temperature, in neutral pH water, and it's easy to set up", Nocera says. "We figured out a way just using a glass of water at room temperature, under atmospheric pressure."In a similar development, Chemist Bjorn Winther-Jensen of Monash University in Australia and his colleagues have made a fuel cell that uses electrodes made from a special conducting polymer that costs around $57 per ounce. During experiments, the polymer proved just as effective as platinum at harvesting electricity.
In order for this to work on the grand scale of a fuel cell stack for a hydrogen vehicle or power plant, "we need to develop a more three-dimensional structure to get thicker electrodes and a higher current per square centimeter," says Winther-Jensen.
References:
Hydrogen Power on the Cheap--Or at Least, Cheaper - Scientific American
Water Refineries? - National Science Foundation
'Major Discovery' Primed To Unleash Solar Revolution: Scientists Mimic Essence Of Plants' Energy Storage System - Science Daily
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Comments: 35
I have been aware of the need for the platinum in the electrolysis side of this for the fuel cells as well as the hydrogen harvesting.
We can move forward now with the technology of the fuel cell power. Hydrogen being less combustible than gasoline should also provide for safer means of power for transportation in the future.
The second requires more thought. That is that hydrogen is not a source of energy.
That is, for each joule of energy from hydrogen that is used, a joule (at least) of energy must be used from some other source to generate the hydrogen.
Electricity is exactly the same kind of what I would call "energy currency." That is, for each joule of electrical energy used, at least a joule of energy must be created from another source to create the electricity. Therefore, electricity, the ultimate clean energy force, is criticized (and rightly so) for coal fired power plants. If hydrogen were to come into common usage, then the criticism would be of coal fired hydrogen plants.
Thanks for the article!
~ Alex
Currently, most hydrogen is produced from natural gas. Eventually, I foresee most hydrogen to be produced from water with solar and wind energy. As more wind turbines become operational, there will be a growing surplus of electricity at night, when there's plenty of wind but little demand for electricity. It makes sense to use this electricity surplus for the production of hydrogen. Since off-shore wind turbines can produce twice as much electricity as land-based turbines, I expect the Hydrogen Economy to take off at seaports, supplying hydrogen to ships, cars, buses and trucks in the area.
Bill: "...for each joule of energy from hydrogen that is used, a joule (at least) of energy must be used from some other source to generate the hydrogen."
Of course, energy is lost in any conversion process. Hydrogen from natural gas is somewhere around 70% efficient, while electricity (at your meter) is only around 30% efficient from the coal mine. In other words, this is not a major problem, since hydrogen efficiency is actually superior than many of the energy transfers currently in use.
The main 'breakthrough' we're waiting for is not a technological one, but a global commitment to reduce emissions in the most effective way, which IMO is through a framework of feebates, specifically by adding fees to fossil fuel and using the proceeds to fund local rebates on better ways to power, say, ships.
Blessings ~
Rene
A UK team including scientists from the Universities of Birmingham and Oxford, and the Rutherford Appleton Laboratory in Oxfordshire has been testing thousands of solid-state compounds in search of a light, cheap, readily available material which would absorption/desorpt hydrogen rapidly and safely at typical fuel cell operating temperatures.
In May 2007, they reported to have produced a variety of lithium hydride (specifically Li4BN3H10) that could offer the right blend of properties.
The one thing I see that is the most important is to NOT look at big corporations/power plants to facilitate these new power sources. Smaller companies and residencies could help produce extra energy for the grid given fair tax credits (in the beginning) and a standardized buy/sell rate of the commodity. We are all in this together so we need to start thinking of pulling own weight and giving just a little back...
Catalysts are used inside electrolyzers to jump start chemical reactions that break water down into hydrogen and oxygen, as electricity is fed into the electrolyzer. "Owing to the self-healing properties of the catalysts, these electrolyzers can use any water source," including seawater, waste water or water from the Charles River in Boston, the researchers say.
Electrolyzers can be powered by surplus electricity at off-peak times, producing hydrogen and oxygen that is stored into tanks. When needed, the stored hydrogen and oxygen can then be recombined in a fuel cell to produce electricity (and clean drinking water as a byproduct).
The new catalyst has been licensed to Sun Catalytix, founded by Dan Nocera, to develop safe, super-efficient versions of the electrolyzer that are suitable for homes and small businesses within two years. Sun Catalytix mentions that just 3 gallons of water contains enough energy to satisfy the daily energy needs of a large American home.
Sandia's work and the work at at the Swiss Federal Institute of Technology, Zurich, are described recently in New Scientist.
Producing hydrogen in this way has been done for years. In further work in Europe, a team led by Athanasios Konstandopoulos has successfully managed to split carbon dioxide into carbon monoxide and oxygen in this way.
Hydrogen and carbon monoxide can subsequently be combined into hydrocarbons, i.e. synthetic oil.
Daniel Nocera, Ph.D. described an advanced solar cell the size of a poker card but thinner. The device is fashioned from silicon, electronics and catalysts, substances that accelerate chemical reactions that otherwise would not occur, or would run slowly. Placed in a single gallon of water in a bright sunlight, the device could produce enough electricity to supply a house in a developing country with electricity for a day, Nocera said. It does so by splitting water into its two components, hydrogen and oxygen.
The hydrogen and oxygen gases would be stored in a fuel cell, which uses those two materials to produce electricity, located either on top of the house or beside it.
Nocera’s new leaf is made of inexpensive materials that are widely available, works under simple conditions and is highly stable. In laboratory studies, he showed that an artificial leaf prototype could operate continuously for at least 45 hours without a drop in activity.
The key to this breakthrough is Nocera’s recent discovery of several powerful new, inexpensive catalysts, made of nickel and cobalt, that are capable of efficiently splitting water into its two components, hydrogen and oxygen, under simple conditions. Right now, Nocera’s leaf is about 10 times more efficient at carrying out photosynthesis than a natural leaf. However, he is optimistic that he can boost the efficiency of the artificial leaf much higher in the future.