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Bio-Platinum Hybrid Catalyst for Solar Hydrogen Production Can Deliver Up to 25x Greater Energy Yield Than Current Biomass-to-Fuel Strategies

Schematic of the electron flow in the photosystem I catalytic nanoparticle. Source: Iwuchukwu et al., Nature Nanotechnology. Click to enlarge.

Researchers at the University of Tennessee at Knoxville have shown that a combination of photosystem I from a thermophilic bacterium and cytochrome-c6 can, in combination with a platinum catalyst, generate a stable supply of hydrogen in vitro upon illumination. A paper on their work was published online 8 November in the journal Nature Nanotechnology.

The system produces hydrogen at temperatures up to 55 °C (131 °F) and is temporally stable for >85 days with no decrease in hydrogen yield when tested intermittently. The maximum yield is ~5.5 mmol H2 h-1 mg-1 chlorophyll and is estimated to be ~25-fold greater than current biomass-to-fuel strategies. If scaled linearly, a solar collector 1 acre in size with a solution depth of 10 cm operating at 55 °C would be capable of producing hydrogen with an energy yield equivalent to that of 300 litres of gasoline per hectare per day (gross yield, ignoring production separation and distribution energy costs).

Current biomass-to-fuels schemes yield relatively low fuel value per unit land area, the authors note. One way to improve production yield is to use solar energy directly, as plants do in photosynthesis.

In oxygenic photosynthesis, two reaction centers, photosystem II and photosystem I (PSI), function together to transfer electrons derived from water, producing both oxygen and ATP. Several studies have shown that coupling either platinum nanoclusters or covalently linked hydrogenase to the acceptor end of PSI complexes can harvest the photochemically produced electrons to reduce protons to hydrogen in vitro.

The University of Tennessee team showed that a stable supply of hydrogen can be generated using a platinum catalyst and a system made of PSI isolated from the thermophilic cyanobacterium T. elongatus and a recombinant form of cytochrome-c6 (cyt c6) protein.

This potential yield [300 litres of gasoline per hectare per day] is more than an order of magnitude higher than the gross yield in terms of gasoline equivalents of agricultural biomass systems such as corn-based ethanol (5.43 litres per day per hectare), soy based biodiesel (1.42 litres per day per hectare) or projected yields of switchgrass-produced ethanol (12.1 litres per day per hectare). Comparing this fuel production rate to the average available solar radiation at latitudes in the middle of the US, this system is capable of converting ~6% of solar radiation into usable fuel.

This system provides a more direct route to fuel production with no need for the harvesting, converting, fermenting and distilling processes involved in conversion of biomass to ethanol. Moreover, other processing and transportation costs would be much lower because the bio–platinum hybrid catalyst is reused through many cycles, unlike in single-use methods such as biomass accumulation.

Finally, the fact that our PSI operates with high thermal tolerance suggests that this approach may be viable in non-arable regions with high solar irradiances. This is in contrast to the cultivation of biofuels that may compete directly with agricultural production.

—Iwuchukwu et al.

(A hat-tip to Matt!)


  • Ifeyinwa J. Iwuchukwu, Michael Vaughn, Natalie Myers, Hugh O’Neill, Paul Frymier & Barry D. Bruce (2009) Self-organized photosynthetic nanoparticle for cell-free hydrogen production. Nature Nanotechnology doi: 10.1038/nnano.2009.315



Well, maybe it's time for me to reconsider my total skepticism about a hydrogen economy. The problem was always, "where's all that hydrogen going to come from?"


6% to chemical fuel is pretty good, but if your final destination is motive you need to divide this by 2,3 or 4 to account for fuell cell / ICE efficiency. (sun to wheels)

PV battery charging should be around 10-15% (sun to wheels)


danm summed it and there should be more fanfare, if the numbers and economics are good.


Fascinating. Platinum remains expensive. 55C appears to be a nominal temp for their yield. And they do not factor energy for "production separation and distribution."

But, given the process works, it will certainly be a contender in the H2 evolution. And it requires no exotic physics. Desert states Arizona, Utah, New Mexico, become contenders for h2 production facilities. Very cool in a 55C kinda way.

Henry Gibson

Fine report until the first word, bio-platinum. There is not a word about how many pounds of platinum are needed to cover the acre with the bio-catalyst or how much it costs to make the catalyst or what the ultimate life of the catalyst is. Just mention hydrogen and bio-fuel and solar energy and the true believers in a false doctrine will come flocking. The false doctrine, with its varients, is that solar energy is the only useable, renewable, free energy.

The laws of physics discovered a few hundred years ago that there is no renewable energy. Billions of tons of hydrogen are wasted just to produce solar energy for the earth. The earth only receives one part in two billion of the sun's output of energy.

We should shut down the sun and save the hydrogen until fusion reactors are built on the earth in fifty years. Fusion reactors will be able to produce more and better plutonium for bombs than was ever dreamed of by the first fission reactor builders. Uranium centrifuges make any kind of reactor for producing bomb plutonium too expensive and very obsolete.

There is also the question of the cost of the ground. Congress is now debating putting aside many thousands of acres of land in the western US to prevent its development. Just try to buy an acre of land near any city or far from any city.

Next you must pay the cost of covering this area with glass or plastic to prevent the escape of the hydrogen.

How do you keep the solution at 55 degrees centigrade (131 F) without insulating it.

The other costs are hinted at. "(gross yield, ignoring production separation and distribution energy costs)" The same oil fields that still, even now, vent and flare natural gas would even be more likely to vent and flare hydrogen, if it were present, because of the expense of collecting and transporting it. Landfills vent and flare methane and would be even more likely to do the same with hydrogen.

If Saudi Arabia had no oil but only the equivalent amount of hydrogen comming from their wells they would not sell near as much energy and would envy Irag which had oil. They would even envy countries that only had natural gas that can be shipped more easily. In todays, justifiably, anti CO2 attitude they would find a way to sell a lot of hydrogen, but very few would run cars on it. Eventually they would import CO2 and use it with the hydrogen to make liquid fuels. Methanol might even be the preferred fuel even though it costs more to transport.

They would be tempted to extract CO2 from mountains full of minerals to make liquid fuels. This could be even considered carbon neutral because the mineral product would collect CO2 from the air when made into buildings. They would also make and sell ammonia for use as a fuel, since it can be shipped as a liquid.

Pebble bed nuclear reactors can produce a high enough temperature to thermochemically produce hydrogen from water as can some other types of reactors. These do not take much land area at all and can produce about a million pounds of hydrogen from a pound of uranium from a dismantled warhead or similar uranium or plutonium from other sources. Rubbia reactors can produce energy at low cost and very high temperatures from thorium. CANDU reactors with reprocessing can also produce energy from thorium alone once started with uranium or plutonium, but they do not produce any surplus fuel for other reactors as breeder reactors do.

Fossil fuel would not be used as a perjorative term, if it were not for the predicted rise in temperature and ocean levels that may inconvenience the human race. Most environmentalists, however shallow or deep their convictions, promote ideas and actions that logically would lead to the conclusion that nature and the earth would be better off without humans. This brings up the very uncomfortable question: do humans have a right to exist. If so how many? If humans are a part of nature, what we do is natural and good for the earth. Bacteria do not worry about producing antibiotics to kill their neighbors they just do it to protect themseves and their food supplies.

If humans are not part of the nature of the earth, we are now smart and rich enough to live on the moon since we have discovered fission energy and ways to use solar energy more efficiently than eating and burning plants and fossilized plants.

With no humans on the earth all life forms would be subjected to high and low sea levels and high and low levels of CO2 and other gases in the air as they were in the past and nobody would need to complain.

Only a few ten thousands of years ago there were very few humans on the earth and a large number of various plants and animals that no longer exist. The human race almost did not survive the last major ice age. The reason that there are so many people on the earth now is directly due to the discovery and clever use of fossil fuels including the industrialization of the human race which includes especially transportation.

Millions of people would die of starvation every year in the US in local famines if there were no transportation and communication. Tens of thousands did prior to the railroads in the US. Millions of people do in the rest of the world today because they do not have access to the transportation of food from afar.

Foods can be and are made directly from fossil fuels. Ethanol made from crude oil or natural gas in the millions of tons each years is nearly as good a food as its cousin VODKA which many rely upon for a large part of their daily calories. Ethanol from some chemical companies must be more pure for its intended use than ethanol from corn.

Fossil fuels are used to increase the production of food on almost all farms. Many sales of "organic" food would not take place if only "organic" fuels were allowed to produce, package and transport such foods.

All forms of energy, including oil and solar, used on the earth are delivered free by nature, but humans must collect it to use it as must all other life forms. The lower the collecting and use cost, the more life there can be.

Rather than spending hundreds of billions of dollars on protecting people from the least exposure to radiation from nuclear power plants or YUCCA mountain, the US should use nuclear fission and in, fifty years, fusion energy to extract CO2 from the air and make vast mountains of pure carbon from it easily accesible to the next generations of humans and far more lives will be protected and promoted. ..HG.. May the hydrogen be with you!


Hey HG quite a discourse. Perhaps singing to the choir a little. Have a great day and I look forward to more of your insight.

Henry Gibson

There have been more funds allocated to the study of producing the space elevator. When it is built another should be built in the form of a tube. The hydrogen that represents most of the molecules in the vacuum of space near the earth can be collected with solar energy and pumped into the tube that then takes it to the surface of the earth. The hydrogen can be burned until the earths oxygen gets very low. There will be a large supply of pure fresh water. All land can then be cleared from the clutter of solar collectors and windmills and dams and lakes and returned to their natural GAIA given condition. ..HG..


Henry Gibson - "We should shut down the sun and save the hydrogen until fusion reactors are built on the earth in fifty years."

So it is fifty years now. Fusion has been twenty years away for the last thirty or so years now. Are you now saying it is fifty years away?

As for the rest of your rambling discourse - does the term "jumping the shark" mean anything to you?


Actually fusion was promised to be 20 years away back in the 1960s just as I was getting out of grad school.

The Tokomak research device has yet to break even in energy terms. Even if that goal is reached this technology will never be practical because of scaling.


"and is temporally stable for >85 days"
LOL dream on.


Cost matters too. Nanosolar and first solar are both printing PV cells at $1 per watt right now.

If we cared, we could easily build 1,000 1 GW printers around the world this year, then we'd be getting 1 TW of solar cells printed every year (the USA electricity consumption averages ~0.45 TW).


"We should shut down the sun and save the hydrogen until fusion reactors are built on the earth in fifty years. "

Gol dernit... Where is that OFF switch fer the sun??

Carlos Fandango

Clett's right.

We should also spend billions on battery plants instead of sticking notes down bankers bikinis.

Roger Pham

6% solar to hydrogen efficiency is still a lot lower than a typical solar PV at 15% efficiency. The use of Platinum is a disadvantage here. The problem of direct solar to hydrogen is that of transporting that gaseous hydrogen a vast distance to the site of H2 consumption.
By contrast, it is far easier to transport electricity via power lines. HVDC power lines can transmit electricity with low lost for thousands of miles. The solar electricity from PV panels can displace fossil fuel used in power plants, and only excess solar PV electricity is used to produce H2 for later use. The H2 can be produced near the site of retail using grid electricity, thus overcoming the inefficiency of long-distance transportation of H2.
GE has invented a low-cost method of electtrolysis of water without using Platinum, a rare metal.

Don't worry, Henry Gibson, the sun will shine for a few billion more years. However, in less than a billion year from now, the sun will get so big that everything on earth will be vaporized from the heat. Perhaps, by then, human or another intelligent life form on earth will perfect nuclear fusion energy on earth in order to decelerate the earth into an orbit much farther from the sun than now. May be they will find another scheme to decelerate the earth's orbital speed around the sun.


Since our sun will very likely be around for another 5+ billion years, it would be wise to use current and future higher efficiency solar cells worldwide to collect all the energy the human race requires. Energy storage problem will be solved within another decade. Much lower cost e-storage devices will do it domestically and/or at the energy sources.

Most house owners, with a 100+ M2 roof covered with high efficiency PVs and a 20+ KWh e-storage unit could produce all the energy needed without power lines, distribution networks, coal fired power plants, nuclear power plants etc.


clett, This is the type of cells we expect great things from?can you tell more?

October 26, 2009...Australian semiconductor company, BluGlass Limited, has been awarded $4.96 million of Commonwealth Government funding to assist with the development and commercialization of its high efficiency thin-film solar cell technology. BluGlass has secured the funding under Climate Ready Program which is one of the three elements of the $240 million Clean Business Australia initiative. The 'High-Efficiency Thin-Film Solar Cell' project aims to develop a third generation photovoltaic technology for manufacturing high efficiency solar cells based on the compound semiconductor material, indium-gallium nitride (InGaN). AusIndustry, the Australian federal government's program to provide assistance to industry, will provide the cash to BluGlass over 33 months. As part of the funding agreement BluGlass will match the AusIndustry funding with its own expenditure.

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