Energy

Stable and scalable photo-electrode “strongest candidate yet” for renewable hydrogen generation

University of Exeter researchers have created a semiconductor material that is "the strongest candidate yet for renewable hydrogen generation"
University of Exeter researchers have created a semiconductor material that is "the strongest candidate yet for renewable hydrogen generation"
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University of Exeter researchers have created a semiconductor material that is "the strongest candidate yet for renewable hydrogen generation"
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University of Exeter researchers have created a semiconductor material that is "the strongest candidate yet for renewable hydrogen generation"

Using the power of the sun to split water and produce hydrogen fuel is one of the most promising clean energy technologies being pursued. One of the biggest hurdles holding it back has been uncovering an efficient and stable semiconductor material for use in the water-splitting process, but that's just what a team from the University of Exeter now claims to have created.

Not only does using an artificial photosynthesis process to split water into its constituent hydrogen and oxygen atoms promise to be clean and produce zero carbon emissions, but the resulting hydrogen has more than double the energy density of fossil fuels and, when used, the only by-product is water. It would also provide an essentially limitless source of energy.

In the quest to reach this goal, the University of Exeter team has built a new photo-electrode, which absorbs light and triggers electrochemical transformations that extract hydrogen from water, using nanoparticles of lanthanum, iron and oxygen. Its creators claim the lanthanum iron oxide semiconducting material, which is produced using a cheap spray pyrolysis technique followed by a post annealing step, is "the strongest candidate yet for renewable hydrogen generation" as it is stable, low-cost, and should be scalable for mass use worldwide.

"We have shown that our LaFeO3 photo-electrode has ideal band alignments needed to split water into its constituents (H2 and O2) spontaneously, without the need of an external bias," says Govinder Pawar, the lead author of the paper. "Moreover, our material has excellent stability where after 21 hours of testing it does not degrade, ideal for water splitting purpose. We are currently working on further improving our material to make it more efficient to produce more hydrogen."

The team's research appears in the journal Scientific Reports.

Source: University of Exeter

9 comments
DFrancis
Beautiful circular energy system: start with water, split it, oxidize the hydrogen, and recover the original substance - water. Invokes images of clean air, blue skies and lush green foliage. Oh, and shiny vehicles that hum as they whoosh by.
JimFox
"the resulting hydrogen has more than double the energy density of fossil fuels" How so? Hydrogen being the lightest element has extremely low 'energy content' per cu.m. It must be compressed to 10,000 psi for use in EV fuel cells, for instance.
guzmanchinky
Just when you thought Hydrogen was dead as a fuel source...
nick101
As someone has previously pointed out, "the resulting hydrogen has more than double the energy density of fossil fuels " is incorrect. Hydrogen must be compressed to be useful, sometimes the energy used to compress it is more than the energy you get out of it. If the gas coming out of a device was 145 PSI then you'd really have something!
notarichman
storing and compressing the hydrogen? the actual engine? thermocouples for electricity? doubt it. actual energy produced per square foot versus best solar cells in production?
SimonClarke
With the current technology of Batteries is there any need for Hydrogen as a fuel for vehicles? I know I like to cook with gas and hydrogen can be used for that but cars with 500+ mile ranges and others that charge 250 miles in 15 minutes are on the horizon. Is this Hydrogen technology really needed.
Douglas Bennett Rogers
This could be the basis of a pelagic farming community.
fen
@Simon Clarke - Well you will need to replace the batteries on an electric car. You wont need to replace the tank on a hydrogen car. Electricity fails in big cities all the time with rolling black outs. If a high pressure tank can be made greenly (carbon), and the hydrogen can be made greenly, then why would you argue that an existing solution that can not be made greenly (batteries) is better? We need to go for the greenest solution, and that is local areas being able to create and pool the energy, even if half of it is lost, even if 90% is lost, if its chugging away creating no pollution and needing no upgrades on an ongoing basis that pollute, then its a great system.
Bruce H. Anderson
It would be interesting to see how this might scale up. Questions like how much water would be needed? What percentage of that water gets split into H2 and O2? Where does the extra water go? Are there any fouling concerns? How efficient would it be in environments with less sun (northern climes) as opposed to where there is lots of sun (and sometimes little water). What size of an array would be necessary to produce an equivalent amount of energy to, say, 1,000 barrels of crude? What is the plan and/or consequences for releasing the O2 to the atmosphere?