Chemists have learned to make graphene from waste

Scientists have developed a new method for the synthesis of graphene, for which the source reagent is good anytime
solid with a high carbon content, including food residues,
charcoal, petroleum coke, tires or mixed
plastic waste. This method managed to get a poorly ordered graphene
with a purity of up to 99 percent, write the authors in the journal Nature.

Graphene is one of the
allotropic modifications of carbon, which is a flat sheets
the atomic thickness. Graphene
has several unique mechanical, chemical and electronic properties that
potentially makes it attractive to a large number of fields of science and
equipment. However, at the moment, broad applications of graphene is not, as existing
methods for the synthesis of substances suitable to produce either tiny amounts
high-quality samples, or for industrial synthesis undirected
flakes of poor quality.

Most of the ways
obtaining large-scale graphene is based on the top-down approach, that is,
in one form or another uses the delamination of graphite by oxidation to
oxide, and then restores the resulting compound to the individual scales
graphene. It uses a powerful and dangerous oxidizing agents, and material on
the output is usually of low quality due to the presence of defects. The approach “bottom-up”,
on the other hand, is used for the synthesis of single sheets of high quality
for example, by deposition from the gas phase. Some of these methods
can be scaled, but in this case, it is also unable to maintain a high
the quality of the product.

American chemists under
the leadership of James Tour (James Tour) from rice University have invented a new
a method that partially combines the advantages of two existing approaches.
The authors showed that the transmission of a powerful pulse of electric current through
rich carbon substance leads to the synthesis of a large number of graphene
moreover, the substrate can be the most common and cheapest products, which
you need to chop and place in a ceramic capacitance between the electrodes. In
the result with reasonable power consumption and without the use of caustic chemicals could
for one inclusion to up to several grams turbostratic graphene, that is, having
a layered structure but with randomly rotated layers.

The work is based on
previous studies of this group, in which graphene was obtained by using
irradiation of carbon laser pulses. Then scientists learned about
the work of another group, in which metal nanoparticles have received by using
bandwidth powerful current, which should have approximately the same effect
— sharp heat.

Subsequent
experiments with the hybrid method has allowed to find the parameters of the electric pulse,
suitable to achieve the necessary three thousand Kelvin, and detailed
the study of samples confirmed the formation of graphene. The original substrate is almost
completely evaporates within ten milliseconds, and then the carbon atoms
are arranged in the desired configuration from the gas phase.

The authors note that
the resulting material is well suited as additives in, for example,
construction materials such as concrete and asphalt, and plastics. In
specifically, researchers have determined that the addition of synthesized
graphene in the amount of 0.05 percent by volume increases the strength
the compression of the concrete in the quarter. There are also initiatives to improve using
the graphene road surfaces and paints.

Previously, scientists have improved the catalytic properties of graphene with bird droppings, turned it into an anomalous magnet and offered to reduce the cost of its production hundreds of times with the use of eucalyptus bark.

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