#Graphene oxide soaks up radioactive waste: U s.,Russian researchers collaborate on solution to toxic groundwater woesgraphene oxide has a remarkable ability to quickly remove radioactive material from contaminated water researchers at Rice university
A collaborative effort by the Rice lab of chemist James Tour and the Moscow lab of chemist Stepan Kalmykov determined that microscopic atom-thick flakes of graphene oxide bind quickly to natural and human-made radionuclides
Graphene oxide's large surface area defines its capacity to adsorb toxins Kalmykov said. So the high retention properties are not surprising to us he said.
which it can react there is a greater likelihood that the'magic'will happen with graphene oxide than with a big old hunk of bentonite said Steven Winston a former vice president of Lockheed martin
The lab tested graphene oxide synthesized at Rice with simulated nuclear wastes containing uranium plutonium
Even so graphene oxide proved far better than the bentonite clays and granulated activated carbon commonly used in nuclear cleanup.
Graphene oxide introduced to simulated wastes coagulated within minutes quickly clumping the worst toxins Kalmykov said.
Where you have huge pools of radioactive material like at Fukushima you add graphene oxide
Graphene oxide burns very rapidly and leaves a cake of radioactive material you can then reuse.
The low cost and biodegradable qualities of graphene oxide should make it appropriate for use in permeable reactive barriers a fairly new technology for in situ groundwater remediation he said.
and packing at electrode surfaces the team combined knowledge about graphene and organic crystals. Though it was difficult Briseno says they managed to get the necessary compounds to stack like coins.
We had exploited essentially every substrate possible until we finally succeeded with graphene he adds which happened by accident
#Graphene imperfections key to creating hypersensitive electronic noseresearchers have discovered a way to create a highly sensitive chemical sensor based on the crystalline flaws in graphene sheets.
When a graphene lattice or sheet is formed its polycrystalline structure has random boundaries between the single-crystal grains.
But Salehi-Khojin and his colleagues showed that these imperfections are important to the working of graphene-based gas sensors.
They created a micron-sized individual graphene grain boundary in order to probe its electronic properties and study its role in gas sensing.
and accumulate there rather than on the graphene crystal making it the ideal spot for sensing gas molecules.
Salehi-Khojin said it should be possible to tune the electronic properties of graphene grain-boundary arrays using controlled doping to obtain a fingerprint response
The material is made of graphene nanoribbons atom-thick strips of carbon created by splitting nanotubes a process also invented by the Tour lab
This scanning electron microscope image shows the network of conductive nanoribbons in Rice university's high-density graphene nanoribbon film.
The graphene-infused paint worked well Tour said but where it was thickest it would break down
This scanning electron microscope image shows a closeup of the nanoribbon network in Rice university's high-density graphene nanoribbon film.
but testing showed the graphene nanoribbons themselves formed an active network when applied directly to a surface.
Physicists find 2-D form pays no heed to defectsdefects damage the ideal properties of many two-dimensional materials like carbon-based graphene.
Like perfect graphene--but unlike imperfect graphene--it performs as expected. View 2-D phosphorus from above and it looks like graphene boron nitride or other dichalcogenides with its rows of hexagons.
But at an angle phosphorus reveals its true form as alternate atoms jut out of the matrix.
#New test reveals purity of graphene: Scientists use terahertz waves to spot contaminantsgraphene may be tough
Because it's so easy to accidently introduce impurities into graphene labs led by physicists Junichiro Kono of Rice
They expect the finding to be important to manufacturers considering the use of graphene in electronic devices.
It was made possible by the Rice-based Nanojapan program through which American undergraduates conduct summer research internships in Japanese labs. Even a single molecule of a foreign substance can contaminate graphene enough to affect its electrical and optical properties
The researchers used it as a substrate for graphene. Hitting the combined material with femtosecond pulses from a near-infrared laser prompted the indium phosphide to emit terahertz back through the graphene.
Imperfections as small as a stray oxygen molecule on the graphene were picked up by a spectrometer.
The change in the terahertz signal due to adsorption of molecules is said remarkable Kono. Not just the intensity but also the waveform of emitted terahertz radiation totally and dynamically changes in response to molecular adsorption and desorption.
The laser gradually removes oxygen molecules from the graphene changing its density and we can see that Kono said.
The experiment involved growing pristine graphene via chemical vapor deposition and transferring it to an indium phosphide substrate.
Laser pulses generated coherent bursts of terahertz radiation through a built-in surface electric field of the indium phosphide substrate that changed due to charge transfer between the graphene and the contaminating molecules.
For any future device designs using graphene we have to take into account the influence of the surroundings said Kono.
Graphene in a vacuum or sandwiched between noncontaminating layers would probably be stable but exposure to air would contaminate it he said.
The Rice and Osaka labs are continuing to collaborate on a project to measure the terahertz conductivity of graphene on various substrates he said.
Researchers unzip nanotubes by shooting them at 15,000 mphcarbon nanotubes unzipped into graphene nanoribbons by a chemical process invented at Rice university are finding use in all kinds of projects
One-step chemical-free clean and high-quality graphene nanoribbons can be produced using our method. They're potential candidates for next-generation electronic materials he said.
diselenide--a highly sought semiconductor that is similar to graphene but has better properties for making certain electronic devices like switchable transistors and light-emitting diodes.
Unlike graphene which can now easily be made in large sheets many interesting 2-D materials remain difficult to synthesize.
because they have an atomic structure similar to graphene the pure carbon wonder materials that attracted the 2010 Nobel prize in physics.
Graphene and similar materials are referred often to as two-dimensional because they are only one atom thick.
Graphene has extraordinary electronic properties. For example its electron mobility is tens of thousands of times greater than that of TMDCS.
because their electronic properties are complementary to graphene. For example pure graphene has no bandgap--a useful electronic property that engineers can exploit to make FETS that are switched easily on and off.
As with many nanomaterials scientists have found that the physical properties of TMDCS change markedly when the material has nanoscale properties.
and efficiency of excited hot electrons drawn from gold nanoparticles into a sheet of graphene. It's a good thing for scientists
Dark-field scattering and photoluminescence spectroscopy of more than 200 nanoparticles helped them determine that it takes about 160 femtoseconds (quadrillionths of a second) for an electron to transfer from the particle to highly conducting graphene the single-atom-thick form of carbon.
The researchers placed gold nanorods on beds of both inert quartz and highly conductive graphene and used a spectrometer to view the line width of the plasmon-scattering spectrum.
The Rice researchers found graphene broadened the nanorods'surface plasmon response --and shortened its lifetime--by accepting hot electrons.
By acting as an electron acceptor the graphene accelerated damping of the plasmons. The difference in damping between the quartz
and graphene samples provided a means to calculate the electrons'transfer time. The plasmon resonance is determined by the size
which in this case is graphene. The Rice lab hopes to optimize the connection between the nanoparticles
and graphene or another substrate preferentially a semiconductor that will allow them to trap hot electrons.
He noted other researchers are looking at similar effects through the molecular manipulation of graphene the single-atomic-layer form of carbon.
Sydney to London on the Plastic Fantastic powered flight Move over graphene: Bamboo is the next wonder material Friends of Earth rain on Lufthansa biofuels parade Biofuels fly mainstream:
Move over graphene: Bamboo is the next wonder materialstep aside graphene, there's a new super material in town,
and it's a lot more common than you and your honeycombed carbon lattices: bamboo. Bamboo is being hailed as a new super material,
Don't worry graphene. As far as I know, bamboo does not have semiconductor capabilities. Photos:
Goodbye silicon, hello oxides Graphene the Sequel: Graphyne. It s flashier. Paper Cuts: New material could slash CO2,
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