During their testing of the new material, they have discovered that it can store and release hydrogen extremely fast and at low temperatures compared to similar materials. Another important aspect of the new material is that it is also rechargeable. These attributes could make it ideal for use in onboard hydrogen storage for next-generation hydrogen or fuel cell vehicles.
The findings on the performance of the nanoblades are published in the September 2011 edition of The International Journal of Hydrogen Energy in an article titled “Low-temperature cycling of hydrogenation-dehydrogenation of Pd-decorated Mg nanoblades.” The research is sponsored by the National Science Foundation.
The scientists created the magnesium-based nanoblades for the first time in 2007. Unlike three-dimensional nanosprings and rods, nanoblades are asymmetric. They are extremely thin in one dimension and wide in another dimension, creating very large surface areas. They also are spread out with up to one micron in between each blade.
In order to store hydrogen, a large surface area with space in between nanostructures is needed to provide room for the material to expand as more hydrogen atoms are stored. The vast surface area and ultrathin profile of each nanoblade, coupled with the spaces between each blade, could make them ideal for this application, according to Gwo-Ching Wang, professor of physics, applied physics, and astronomy at Rensselaer.
To create the nanoblades, the researchers use oblique angle vapor deposition. This fabrication technique builds nanostructures by vaporizing a material — magnesium in this case — and allowing the vaporized atoms to deposit on a surface at an oblique angle. The finished material is then decorated with a metallic catalyst to trap and store hydrogen. For this research, the nanoblades were coated with palladium.
In their most recent paper, the researchers report on their tests of the nanoblades’ performance. Understanding how the material responds to hydrogen over time is essential to improving the material for future use in hydrogen vehicles, according to postdoctoral researcher and lead author of the new paper Yu Liu.
“The requirements from the Department of Energy are very challenging for existing hydrogen storage technology, particularly when it comes to new energy storage materials for onboard hydrogen storage,” said Liu. “All new materials must operate at low temperatures, desorb hydrogen quickly, be cost efficient, and be recyclable.”
Their work with nanoblades is already showing promise in all these areas, according to Wang and Liu.
What they found is that the nanoblades began releasing hydrogen at 340 degrees K (approximately 67 degrees Celsius). When the temperature was increased slightly to 373 K (100 degrees C), the hydrogen stored in the nanoblades was released in just 20 minutes. Many other materials require more than double that temperature to operate at that rate, according to Liu.
They also found that the nanoblades are recyclable. This means that they can be recharged after hydrogen release and used over and over. Such reusability is essential for practical applications.
Using a technique called reflection high-energy electron diffraction (RHEED) and temperature programmed desorption (TPD) — which are equipped onto an integrated ultrahigh vacuum system with a combination of a high-pressure reaction cell and a thin-film deposition chamber — they found that the current nanoblades can go through more than 10 cycles of hydrogen absorption and release.The RHEED technique is different from other processes, such as X-ray diffraction, because it monitors the near surface structure, phase, and grain size of the material as it changes. Tracking the surface evolution of the material provides insight into how the structure evolves over time.
Using RHEED, they found that over time the catalyst becomes poisoned and the magnesium reacts with oxygen. This causes oxidation, which ultimately degrades the material causing both morphological and chemical changes to the material.
They will now work to optimize the material with different catalysts and polymer protective coatings to improve performance and increase the number of cycles that the material can go through without degradation.
“The next steps are to improve recyclability,” Wang said. “We have found the root cause of the degradation of the material; now we can begin to improve the material.”
Wang and Liu were joined in the research by Professor of Physics, Applied Physics, and Astronomy Toh-Ming Lu and doctoral student Liang Chen. This experimental work received theoretical insights provided by the Gail and Jeffrey L. Kodosky ’70 Senior Constellation Professor of Physics, Information Technology, and Entrepreneurship Shengbai Zhang and doctoral student Wieyu Xie.
Gabrielle DeMarco | Newswise Science News
Multiregional brain on a chip
16.01.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences
Researchers develop environmentally friendly soy air filter
16.01.2017 | Washington State University
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction