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
Solid progress in carbon capture
27.10.2016 | King Abdullah University of Science & Technology (KAUST)
Greater Range and Longer Lifetime
26.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences