PRODUCTION OF REDUCED GRAPHENE OXIDE BY HYDROHALIC ACIDS Samuel Cooke, James Murray Graphene is a material consisting of a 2-dimensional hexagonal lattice of carbon atoms, and has many unique properties such as a very high conductivity and tensile strength. Pure graphene is very difficult to produce on a large scale, so a proposed solution to this problem is to reduce graphene oxide (rGO). Graphene oxide (GO), shown on the left, is an impure form of graphene as it contains epoxy and hydroxyl groups. By removing these impurities, one can create rGO with properties similar to pure graphene. There are many methods of reducing graphene oxide; however, the method which has proven to be the most scalable and efficient is the use of hydrohalic acids, such as HI, as a reducing agent. With the use of a 55% HI solution, rGO with a conductivity of 298 S/cm (Siemens per centimeter) has been produced, which is much greater than most other methods of reduction. A C/O (carbon to oxygen) ratio greater than 14.9 has been achieved, indicating that there are less impurities and that the material works as a better substitute for pure graphene than rGO produced with other methods. The figure shows the HI reacting with different impurities to reduce GO. Water Filtration • By creating nanopores of a certain size, water is able to pass through the membrane without allowing other pollutants such as salt to permeate. • This process is shown in the figure at the right, where the green bubbles represent pollutants. • This could provide a solution to the growing problem of water shortages around the world. Energy Storage • Ultra-capacitors created with rGO could be implemented into buses, with savings of up to $200,000 in gas during the bus’s lifetime. • Energy generated from power plants is often wasted when not used, but the use of ultra- capacitors in tandem with other technologies could store this wasted energy for later use. • The United States currently has only capacity for storage of 3% of possible output. • One must take into account the impacts that this process may have on the environment if performed on a large scale. The production of graphene oxide requires graphite, which mainly is mainly derived from large mining operations. • The use of rGO in ultra-capacitors would reduce the need for batteries which are mainly produced from rare earth elements derived from Chinese mines. This makes the use of rGO important for economic sustainability as well. • Implementation of rGO for water desalination could allow for more Conductivities As shown in this figure, the use of HI as a reducing agent yields a very high conductivity and C/O ratio. The reason that the use of HI is examined instead of HI/AcOH is because of the amount of research done examining HI compared to HI/AcOH is greater. Reducing Agent Conductivity (S/m) C/O Ratio Well Defined Mechanisms HI/AcOH 30400 11.5 HI 29800 12 NH 3 BH 3 -Ammonia Borane 19300 14.2 C 14 H 14 O 2 P 2 S 4 -Lawesson's 4760 Thiourea dioxide/NaOH 3205 5.8 Thiourea dioxide/Ammonia 290 6 NaBH 4 -Sodium Borohydride 82 4.8 HBr 0.0023 3.9 Proposed Mechanisms Zn/HCL 15000 33.5 NaHSO 3 -Sodium Bisulfate 6500 7.9 C 6 H 8 N 2 -Phenylhyrazine 4700 8.5 C 7 H 8 O-Benzyl Alcohol 4600 30 N 2 H 4 -Hydrazine 2420 10.3 Chemical Reduction Ultra-capacitors The implementation of graphene-based ultra-capacitors could cut back on the amount of fossil fuels burned by buses, allowing renewable energy to be used in place of non-renewable forms of fuel.

PRODUCTION OF REDUCED GRAPHENE OXIDE BY HYDROHALIC ACIDS Samuel Cooke, James Murray Graphene is a material consisting of a 2- dimensional hexagonal lattice

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PRODUCTION OF REDUCED GRAPHENE OXIDE BY HYDROHALIC ACIDS

Samuel Cooke, James Murray

Graphene is a material consisting of a 2-dimensional hexagonal lattice of carbon atoms, and has many unique properties such as a very high conductivity and tensile strength. Pure graphene is very difficult to produce on a large scale, so a proposed solution to this problem is to reduce graphene oxide (rGO). Graphene oxide (GO), shown on the left, is an impure form of graphene as it contains epoxy and hydroxyl groups. By removing these impurities, one can create rGO with properties similar to pure graphene.

There are many methods of reducing graphene oxide; however, the method which has proven to be the most scalable and efficient is the use of hydrohalic acids, such as HI, as a reducing agent. With the use of a 55% HI solution, rGO with a conductivity of 298 S/cm (Siemens per centimeter) has been produced, which is much greater than most other methods of reduction. A C/O (carbon to oxygen) ratio greater than 14.9 has been achieved, indicating that there are less impurities and that the material works as a better substitute for pure graphene than rGO produced with other methods. The figure shows the HI reacting with different impurities to reduce GO.

Water Filtration • By creating nanopores of a

certain size, water is able to pass through the membrane without allowing other pollutants such as salt to permeate.

• This process is shown in the figure at the right, where the green bubbles represent pollutants.

• This could provide a solution to the growing problem of water shortages around the world.

Energy Storage• Ultra-capacitors created with rGO

could be implemented into buses, with savings of up to $200,000 in gas during the bus’s lifetime.

• Energy generated from power plants is often wasted when not used, but the use of ultra-capacitors in tandem with other technologies could store this wasted energy for later use.

• The United States currently has only capacity for storage of 3% of possible output.

• One must take into account the impacts that this process may have on the environment if performed on a large scale. The production of graphene oxide requires graphite, which mainly is mainly derived from large mining operations.

• The use of rGO in ultra-capacitors would reduce the need for batteries which are mainly produced from rare earth elements derived from Chinese mines. This makes the use of rGO important for economic sustainability as well.

• Implementation of rGO for water desalination could allow for more sustainable development in nations without access to clean water.

ConductivitiesAs shown in this figure, the use of HI as a reducing agent yields a very high conductivity and C/O ratio. The reason that the use of HI is examined instead of HI/AcOH is because of the amount of research done examining HI compared to HI/AcOH is greater.

Reducing Agent Conductivity (S/m) C/O RatioWell Defined MechanismsHI/AcOH 30400 11.5HI 29800 12NH3BH3-Ammonia Borane 19300 14.2C14H14O2P2S4-Lawesson's 4760Thiourea dioxide/NaOH 3205 5.8Thiourea dioxide/Ammonia 290 6NaBH4-Sodium Borohydride 82 4.8HBr 0.0023 3.9Proposed MechanismsZn/HCL 15000 33.5NaHSO3-Sodium Bisulfate 6500 7.9C6H8N2-Phenylhyrazine 4700 8.5C7H8O-Benzyl Alcohol 4600 30N2H4-Hydrazine 2420 10.3

Chemical Reduction

Ultra-capacitorsThe implementation of graphene-based ultra-capacitors could cut back on the amount of fossil fuels burned by buses, allowing renewable energy to be used in place of non-renewable forms of fuel.