From 2019:
Scientists from Tomsk Polytechnic University (TPU), together with colleagues from the United States and Germany, have found a way to obtain inexpensive catalysts from hexagonal boron nitride or "white graphene." The technology can be used in the production of environmentally friendly hydrogen fuel.
The researchers have found a new way to functionalize a dielectric, otherwise known as white graphene, i.e.hexagonal boron nitride(hBN), without destroying it or changing its properties. Thanks to the new method, the researchers synthesized a polymer nano carpet with strong covalent bond on the samples.
Prof Raul Rodriguez from the TPU Research School of Chemistry & Applied Biomedical Sciences explains:
"For the first time, we have managed to covalently functionalize hexagonalboronnitridewithout strong chemical compositions and the introduction of new defects into the material. In fact, earlier approaches had resulted in a different material with altered properties, i.e. hydrolyzed boron nitride. In our turn, we used nanodefects existing in the material without increasing their number, and eco-friendly photopolymerization."
One of the promising options for using the new material, according to researchers, is catalysts for splitting water in hydrogen and oxygen. With this in mind, polymer carpets functioned as carriers of active substances, i.e. matrices. Nickel nanoparticles were integrated into the matrix. Catalysts obtained were used for electrocatalysis. Studies showed that they could be successfully used as an alternative to expensive platinum or gold.
"One of the important challenges in catalysis is forcing the starting material to reach active centers of the catalyst. "Polymer carpets form a 3D structure that helps to increase the area of contact of the active centers of the catalyst with water and makes hydrogen acquisition more efficient. It is very promising for the production of environmentally friendly hydrogen fuel," says the scientist.
Boron nitride is a binary compound of boron and nitrogen, while hexagonal boron nitride or white graphene is a white talc-like powder with a hexagonal, graphene-like lattice. It is resistant tohigh temperaturesand chemical substances, nontoxic, has a very low coefficient of friction, and functions both as a perfect dielectric and as a good heat conductor. Boron-nitride materials are widely used in the reactions of industrial organic synthesis, in the cracking of oil, for the manufacturing of products of high-temperature technology, the production of semiconductors, means for extinguishing fires, and so on.
From 2018:
Researchers at Rice University in Houston, Texas have identified boron-based "white graphene" nanomaterials as a highly efficient hydrogen storage materials for fuel cells.The structure, called white graphene, consists of layers of boron nitride separated by boron nitride pillars that are exactly 5.2 angstroms tall, or 0.52nm. While this has been identified from simulation, the challenge is to make physical systems with such precise features.
“The motivation is to create an efficient material that can take up and hold a lot of hydrogen — both by volume and weight — and that can quickly and easily release that hydrogen when it’s needed,” said Rouzbeh Shahsavari, assistant professor of civil and environmental engineering at Rice and director of the Multiscale Materials Lab.
Global demand for hydrogen storage materials and technologies is expected to reach $5.4 billion a year by 2021 according to BCC Research.
The analysis of the material took months of calculations on two of Rice’s fastest supercomputers, and Shahsavari and Rice graduate student Shuo Zhao found the optimal architecture for storing hydrogen in boron nitride. One form of the material, hexagonal boron nitride (hBN), consists of atom-thick sheets of boron and nitrogen and is sometimes called white graphene because the atoms are spaced exactly like carbon atoms in flat sheets of graphene.
“The choice of material is important,” he said. “Boron nitride has been shown to be better in terms of hydrogen absorption than pure graphene, carbon nanotubes or hybrids of graphene and boron nitride.
“But the spacing and arrangement of hBN sheets and pillars is also critical,” he said. “So we decided to perform an exhaustive search of all the possible geometries of hBN to see which worked best. We also expanded the calculations to include various temperatures, pressures and dopants, trace elements that can be added to the boron nitride to enhance its hydrogen storage capacity.”
“We conducted nearly 4,000 calculations to try and find that sweet spot where the material and geometry go hand in hand and really work together to optimize hydrogen storage,” he said.
Unlike materials that store hydrogen through chemical bonding, boron nitride is a sorbent that holds hydrogen through physical bonds, which are weaker than chemical bonds. That makes it easier to release the hydrogen for a fuel cell. The corresponding spacing between them in the superstructure is key to maximizing capacity.
“Without pillars, the sheets sit naturally one atop the other about 3 angstroms apart, and very few hydrogen atoms can penetrate that space,” he said. “When the distance grew to 6 angstroms or more, the capacity also fell off. At 5.2 angstroms, there is a cooperative attraction from both the ceiling and floor, and the hydrogen tends to clump in the middle. Conversely, models made of purely BN tubes — not sheets — had less storage capacity.”
Theory says white graphene could hold 8% hydrogen by weight, exceeding the US Department of Energy’s ultimate target is 7.5%, and the models suggests even more hydrogen can be stored in his structure if trace amounts of lithium are added to the hBN.
The pillar structure avoids problems with the irregularities in the flat boron sheets that are also useful for safety.
“Wrinkles form naturally in the sheets of pillared boron nitride because of the nature of the junctions between the columns and floors,” said Shahsavari. “In fact, this could also be advantageous because the wrinkles can provide toughness. If the material is placed under load or impact, that buckled shape can unbuckle easily without breaking. This could add to the material’s safety, which is a big concern in hydrogen storage devices.
“The high thermal conductivity and flexibility of BN may also provide additional opportunities to control the adsorption and release kinetics on-demand,” he said. “For example, it may be possible to control release kinetics by applying an external voltage, heat or an electric field.”
It gives you an idea why the share price has plummetted after the pump and why it's likely to take a long long time to get to $13.50 again.
How did it get to $13.50 in the first place?
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