JAN 30, 2014 12:00 AM PST

New Atomic Layer Catalyst for Cleaner Hydrogen Production

WRITTEN BY: Jen Ellis
Hydrogen has been proposed as a greener fuel for automobiles of the future, among other novel uses. However, the lack of an inexpensive method of generating hydrogen has held back development of mass produced hydrogen-powered devices. Currently, hydrogen is commercially produced via hydrocarbon processing paths, which do not produce a net positive impact on the environment.

To attain a cleaner source of hydrogen, for years researchers have been working on variations of hydrogen production through solar-powered splitting of water - using solar power to generate electricity, and in turn using that electricity to remove the hydrogen from water. These paths rely on costly platinum catalysts, making the scale-up economics unfavorable for larger scale production.

A group of researchers from North Carolina State University may have solved this problem through their research into alternate catalysts. They found Molybdenum Sulfide (MoS2) to be an effective catalyst, but only at very low thicknesses, with a single atomic layer of less than 1 nanometer being preferential. The work was published online in the recent edition of Nano Letters.

For years, scientists have thought that the catalytic effect took place primarily on the edges of catalysts, and therefore that thicker catalyst layers are more efficient. Extremely thin films were expected to have little catalytic effect, if any. The team discovered that the conductivity of the thinner MoS2 films were a dominant mechanism - with thinner layers having greater conductivity, the catalytic effect was improved. Adding another layer of MoS2 atoms to the catalyst layer decreased catalytic performance by a factor of almost five.

Aside from just using less material, there are multiple potential advantages to the MoS2 catalyst approach. MoS2 can do double duty in a solar water splitting device, since it is capable of both absorbing the proper wavelengths of light and performing the catalyst function. (Typically different materials are required for each function.) MoS2 also has a near perfect bandgap for solar water splitting applications, approximately 1.8 eV (electron-Volts). MoS2 is also a more common and less expensive material than platinum.

There are still performance and scale-up issues to consider. It isn't known whether these films can reliably reach the same efficiency as platinum catalysts, especially on larger scale. Also, the economics of preparing consistently reliable monolayer films at larger scales has to be explored. These monolayers are applied by a CVD (Chemical Vapor Deposition) process, requiring a larger deposition chamber to process larger areas. The group at North Carolina State already has capability of producing high quality monolayer films up to the centimeter scale, which is an important step in the process.

This work is notable for two reasons-the potential for breakthroughs in clean generation of hydrogen fuels, and for shaking up the conventional wisdom in catalyst theory. It's possible that by rethinking the potential for atomic-layer catalysts, scientists will be able to apply this concept in other fields and provide a cascading set of breakthroughs. Meanwhile, the North Carolina State team is turning their attention toward a solar water-splitting system using their new catalyst discovery. Let's all wish them good luck in their efforts.
About the Author
You May Also Like
MAY 23, 2021
Space & Astronomy
More Accurate Clocks Create More Disorder in the Universe
MAY 23, 2021
More Accurate Clocks Create More Disorder in the Universe
Physicists at the University of Oxford in the UK have conducted an experiment that suggests the more accurately clocks t ...
MAY 27, 2021
Neuroscience
Research Less Likely to Be True is Cited More
MAY 27, 2021
Research Less Likely to Be True is Cited More
Researchers from the University of California San Diego have found that non-replicable data is cited 153 times more ofte ...
MAY 26, 2021
Chemistry & Physics
Turning bullfrog skin into human bones - as easy as....?
MAY 26, 2021
Turning bullfrog skin into human bones - as easy as....?
In an effort to support the growth of the circular economy, researchers from Nanyang Technological University, Singapore ...
JUL 19, 2021
Space & Astronomy
Hubble Space Telescope Back from the Brink; In Working Condition after Hardware Swap
JUL 19, 2021
Hubble Space Telescope Back from the Brink; In Working Condition after Hardware Swap
After a month-long hiatus from its routine scientific operations, 31-year-old Hubble Space Telescope (HST) is back in wo ...
AUG 08, 2021
Earth & The Environment
The Surprising Source of Life in the Arctic
AUG 08, 2021
The Surprising Source of Life in the Arctic
According to a new study published in Nature Communications last January, life in the waters of the Arctic Oce ...
SEP 22, 2021
Chemistry & Physics
XENON1T Physicists May Have Directly Detected Dark Energy
SEP 22, 2021
XENON1T Physicists May Have Directly Detected Dark Energy
In what could be a revolutionary discovery, a team of physicists from the XENON Collaboration may have detected dark ene ...
Loading Comments...