Research gives new ray of hope for solar fuel

April 24, 2018, University of Exeter
Credit: CC0 Public Domain

A team of Renewable Energy experts from the University of Exeter has pioneered a new technique to produce hydrogen from sunlight to create a clean, cheap and widely-available fuel.

The team developed an innovative method to split into its constituent parts—hydrogen and oxygen – using sunlight. The hydrogen can then be used as a fuel, with the potential to power everyday items such as homes and vehicles.

Crucially, hydrogen fuel that can be created through this synthetic photosynthesis method would not only severely reduce , but would also create a virtually limitless source.

The ground-breaking new research centres on the use of a revolutionary photo-electrode – an electrode that absorbs light before initializing electrochemical transformations to extract the hydrogen from water – made from nanoparticles of the elements lanthanum, iron and oxygen.

The researchers believe this new type of photo-electrode is not only cheap to produce, but can also be recreated on a larger scale for mass and worldwide use.

The research is published in leading journal, Scientific Reports.

Govinder Pawar, lead author on the paper and based at the University of Exeter's Environment and Sustainability Institute on the Penryn Campus in Cornwall said: "With growing economies and population, will not be able to sustain the in a "clean" manner as they are being exhausted at an alarming rate.

"Alternative renewable fuels must be found which can sustain the global energy demand. Hydrogen is a promising alternative fuel source capable of replacing fossil fuels as it has a higher energy density than fossil fuels (more than double), zero carbon emissions and the only by-product is water."

At present, around 85 per cent of the global energy provisions come from the burning of fossil fuels. Therefore the need and desire to find a sustainable, cost-effective renewable fuel source is growing in urgency.

Perhaps unsurprisingly, the sun is earth's most abundant , with the potential to provide 100,000 terawatts of power each year – meaning one hour's worth of solar energy is equal to an entire year of total energy consumption worldwide.

However, efforts to produce efficient stable semiconductor material, in order to effectively convert sunlight to a storable widespread energy source, have so far proved elusive.

One of the most significant hindrances to the development of viable solar energy has been an inability to produce a semiconducting material suitable for the process.

In this new research, the team utilised lanthanum iron oxide to create a semiconducting material that gave the ideal results for the production of hydrogen from water using sunlight, making it the strongest candidate yet for renewable hydrogen generation.

Govinder Pawar added: "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. 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 ."

"Unbiased Spontaneous Solar Production using Stable LaFeO3 Photoelectrode" is published in Scientific Reports.

Explore further: Plastic 'leaves' turn water into fuel

More information: Govinder S. Pawar et al. Unbiased Spontaneous Solar Fuel Production using Stable LaFeO3 Photoelectrode, Scientific Reports (2018). DOI: 10.1038/s41598-018-21821-z

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10 comments

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dirk_bruere
not rated yet Apr 24, 2018
Efficiency?
theredpill
not rated yet Apr 24, 2018
The efficiency compared to other means of Hydrogen production could end up being magnitudes better, the longer they can make that photo-electrode last. It isn't measurable against Photovoltaic systems designed to produce electricity directly as that is not what this system does.
Parsec
5 / 5 (2) Apr 24, 2018
This is a poorly written article. Rather than a bunch of fluff about how nice it is to convert sunlight into H2, I would have far more preferred more specifics about this particular method. Perhaps comparisons of efficiency with other methods. Discuss the specific reasons why this approach is better, what is needed for future improvements? All questions easily answered in the same space devoted to hyperbole and a poorly veiled sales pitch.
greenonions1
5 / 5 (2) Apr 24, 2018
@dirk - does this statement give you what you wanted?
Hydrogen was being produced spontaneously during the water splitting test during the first 6 hour cycle where the photoelectrode generated 0.18 �Ľmol/cm2 of hydrogen after 6 hours, with a faradaic efficiency of 30%
There is a link at the end of the article that goes to the actual paper.

https://www.natur...-21821-z
Da Schneib
3 / 5 (2) Apr 24, 2018
This is actually a pretty major discovery. What matters now is what limitations it has and how much better they can make it.
NoStrings
5 / 5 (1) Apr 24, 2018
Seriously, 21 hours of testing? Had only two days for the experiments, and publish or perish?
The electrodes should be stable for 21 years to be commercially viable, not 21 hours.
Agree with Mackita, too.
Da Schneib
3.7 / 5 (3) Apr 24, 2018
@macurinetherapy is at it again. Latest claim, photocatalysis of water to make hydrogen "won't work" because it doesn't work in salt water.

Get over it, @macurinetherapy.
24volts
5 / 5 (1) Apr 24, 2018
Mackita, read the entire paper. It's really pretty interesting. When it was being tested there was no outside electrical bias applied to the system at all. Light generated the current to split the water. They need to figure out how to solve the bubble problem it seems though where they affect the voltage output and consequently the gas output.

antialias_physorg
3.7 / 5 (3) Apr 25, 2018
Efficiency?

The linked article gives it as 30% - which is pretty good considering the materials used.Though they have no long term stability measurements yet (they talk about stability over 21 hours...which seems a strangely arbitrary number). The production process requires high temperatures, though. I'm not sure it scales as well as they hope.

Couple of vexing inaccuracies in the article
Crucially, hydrogen fuel that can be created through this synthetic photosynthesis method would not only severely reduce carbon emissions, but would also create a virtually limitless energy source.

Hydrogen is not an energy source but a storage medium. It's more like a battery. (The linked paper gets this correct)

Perhaps unsurprisingly, the sun is earth's most abundant renewable energy source

The sun is *not* a renewable energy source. A renewable energy source is something that doesn't use up any resources here on Earth.
vlaaing peerd
5 / 5 (2) Apr 25, 2018
Batteries are not the way to go if everything needs to be powered with it, so this is good news. Now just a good way to permanently store hydrogen and I think we have the best solution for the near future.

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