Nano-structures to realise hydrogen's energy potential

Aug 15, 2012

(Phys.org) -- For the first time, engineers at the University of New South Wales have demonstrated that hydrogen can be released and reabsorbed from a promising storage material, overcoming a major hurdle to its use as an alternative fuel source.

Researchers from the Materials Energy Research Laboratory in nanoscale (MERLin) at UNSW have synthesised nanoparticles of a commonly overlooked called sodium borohydride and encased these inside nickel shells.

Their unique "core-" nanostructure has demonstrated remarkable hydrogen storage properties, including the release of energy at much lower temperatures than previously observed.

“No one has ever tried to synthesise these particles at the nanoscale because they thought it was too difficult, and couldn’t be done. We’re the first to do so, and demonstrate that energy in the form of hydrogen can be stored with sodium borohydride at practical temperatures and pressures,” says Dr Kondo-Francois Aguey-Zinsou from the School of Chemical Engineering at UNSW.

Considered a major a fuel of the future, hydrogen could be used to power buildings, portable electronics and vehicles – but this application hinges on practical storage technology.

Lightweight compounds known as borohydrides (including lithium and sodium compounds) are known to be effective storage materials but it was believed that once the energy was released it could not be reabsorbed – a critical limitation. This perceived “irreversibility” means there has been little focus on sodium borohydride.

However, the result, published last week in the journal ACS Nano, demonstrates for the first time that reversibility is indeed possible using a borohydride material by itself and could herald significant advances in the design of novel materials.

“By controlling the size and architecture of these structures we can tune theirproperties and make them reversible – this means they can release and reabsorb hydrogen,” says Aguey-Zinsou, lead author on the paper. “We now have a way to tap into all these borohydride materials, which are particularly exciting for application on vehicles because of their highhydrogen storage capacity.”

The researchers observed remarkable improvements in the thermodynamic and kinetic properties of their material. This means the chemical reactions needed to absorb and release hydrogen occurred faster than previously studied materials, and at significantly reduced temperatures – making possible application far more practical.

In its bulk form, sodium borohydride requires temperatures above 550 degrees Celsius just to release hydrogen. Even on the nano-scale the improvements were minimal. However, with their core-shell , the researchers saw initial energy release happening at just 50 °C, and significant release at 350 °C.

“The new materials that could be generated by this exciting strategy could provide practical solutions to meet many of the energy targets set by the US Department of Energy,” says Aguey-Zinsou. “The key thing here is that we’ve opened the doorway.”

Explore further: Atom-thick CCD could capture images: Scientists develop two-dimensional, light-sensitive material

More information: dx.doi.org/10.1021/nn3030018

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User comments : 12

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Cave_Man
1.3 / 5 (4) Aug 15, 2012
For the first time? Lithium hydride has been around for years! Seems to me like a coverup.
MR166
1 / 5 (3) Aug 15, 2012
"Considered a major a fuel of the future, hydrogen could be used to power buildings, ........"

I could not think of a more wasteful way to power a building.

Who writes these articles??????
hemitite
1 / 5 (1) Aug 15, 2012
I just looked up the autoignition temp of H2: 500 C.

Now I know why the release temp of 550 C is a nonstarter!
Shakescene21
5 / 5 (1) Aug 15, 2012
@MR166 -- You need to rethink your definition of "wasteful". Go to Beijing and you will see cheap coal-fired power that is spewing WASTE products (SOX, NOX, soot, and CO2) into the air, destroying peoples lungs, acidifying the oceans, destroying infrastructure, changing the climate, and polluting the West Coast of the US. That is wasteful.
MR166
1 / 5 (2) Aug 15, 2012
Shakescene you need to review your basic physics. In particular, read up on EROEI and you will find that creating H2 and then using it to heat a building results in a huge energy loss regardless of the energy source. BTW there is no such thing as a totally pollution free source of energy. Even solar and wind power are not pollution free.
Cornelius2008
5 / 5 (1) Aug 15, 2012
MR166 I think Shakescene21 and the article are referring to Fuel Cells which from my understanding are alot more efficient than boilers.
Shakescene21
5 / 5 (1) Aug 15, 2012
@MR166 --You need to focus on 21st Century technologies, and to broaden your definition of Waste to include damage to downwind people and environment. I admit that H2 will not be used as much to heat buildings (at first) as it would be for transportation and specialized uses. I think everyone agrees that all energy sources will incur some pollution or environmental damage but fossils fuels are the biggest problem, especially coal and bunker oil. The environmental damage could be reduced dramatically by existing technology and by dramatic new technology, some of which is covered here in Physorg.
Lurker2358
3 / 5 (2) Aug 15, 2012
"Considered a major a fuel of the future, hydrogen could be used to power buildings, ........"

I could not think of a more wasteful way to power a building.

Who writes these articles??????


Agreed.

These idiots do not realize that Hydrogen is only "clean" if the source of the original process to produce that hydrogen is "clean".

Additionally, in almost any case imaginable, direct solar, wind, or geothermal energy will be about 2 or 3 times more productive and efficient for powering buildings than would any hydrogen or natural gas fuel cell or generator.
Cornelius2008
1 / 5 (1) Aug 15, 2012
If you couple hydrogen production with nuclear power you have truly clean hydrogen. Plus due to the quantities produced the low efficiency of splitting water can be ignored.
MR166
1 / 5 (2) Aug 15, 2012
Cornelius you are still better off using the electricity directly and not converting it to a less useful form of energy. This will allow the power produced to reduce the amount of fossil burned by the greatest amount. The energy density of fossil fuels make them ideal for transportation use. To use electricity to produce transportation fuels is counterproductive as long as we are still using fossil fuels to produce electric power. If 100% of our electric power was being generated by non-fossil sources then perhaps H2 could be created by any excess electricity produced.
Cornelius2008
5 / 5 (1) Aug 15, 2012
Mr166 that's exactly what I mean. During low demand excess capacity is used to split water and produce electricity in peak times. Use the hydrogen produced in fuel cells to power vehicles or for applications that can't be wired. The fact that you don't get the same amount of energy out of the hydrogen as you put in at that point doesn't matter because the extra grid capacity takes relatively no increase in operational costs.
javjav
5 / 5 (1) Aug 15, 2012
"Considered a major a fuel of the future, hydrogen could be used to power buildings, ........"
I could not think of a more wasteful way to power a building.

For example, buildings made of glass covered with transparent solar coating. A transparent glass coating that can convert the infrared spectrum of light into electricity is now becoming cost effective for cities with hot weather, as it does not increase the cost of glass production in comparison with infrared insulating layers or smoked glass, and it also reduces the need of air conditioned. But they would also need a cost effective battery with high capacity to store the electricity captured on weekends or at non-peak hours and release it at peak time (when electricity is more expensive), or when no sun is available. Lithium batteries have much lower capacity than a fuel cell, and they are too expensive. In general, this kind of improvements to fuel cells are the key to make solar and wind energy more widely adopted.

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