酸化グラフェン研究の最前線The Cutting Edge of

Graphene Oxide Researches

畠山一翔Kazuto Hatakeyama

Graduate School of Science and Technology, Kumamoto University

ACS Nano 7, 11166 (2013)Angew. Chem. 53, 3588 (2014)

Nano Lett. 12, 3472 (2012)

Humidity sensor

FET

Fuel cell

Adv. Mater. 24, 1748 (2012)

Biosensor

Supercapacitor

Nature. Commun. 4, 1 (2013)

Applications of graphene oxide (GO)

etc…

Graphene

Nature Nanotechnol. 7, 728 (2012) Selective gas sieving

Nano Lett. 12 (7), 3602 (2012) Water desalination

Nano Lett. 14 (3), 1234 (2014) Selective ion sieving

GO

Science 335, 442 (2012)Permeation of water and gas barrier

Nano Lett. 13 (8), 3930 (2013)

Science 342, 91 (2013)Selective gas sieving

Science 342, 95 (2013)

ACS Nano 7 (1), 428 (2013)

Selective ion sievingACS Nano 8 (1), 850 (2014)

Science 343, 752 (2014)

Angew. Chem. in press

Publication about selective membrane using graphene and GO

Limit of selective membrane

Trade-off

Selectivity

Flow

Graphene and GO have a potential to break out of the limit.

HighLow

High Low

Thick membraneThin membrane

High selectivityHigh flow

• Ultimate 2D structure• Perfect molecular barrier (graphene)• Mechanically strong• Good stability• Easy production and low cost (GO)

Porous graphene or GOGraphene GO

Graphene

Nature Nanotechnol. 7, 728 (2012)

Before etch After etch

Selective gas sieving

Molecular size (nm)

H2 CO2 Ar N2 CH4

0.29 0.33 0.34 0.36 0.38

Nano Lett. 14 (3), 1234 (2014)

Allura Red AC (RC)Before etch After etch

(25min < etch time <50 min)

Selective ion sieving

Graphene oxide

GO solution

Filtration

Spin-coat

GO membrane Cross section

• High flexibility• High stability• High mechanical strength

Facile method

GO membrane

Water

Science 335, 442 (2012)Permeation of water and gas barrier

Ultrafast permeation

High barrier

Gas and other liquids

GO membrane

Mechanism of gas barrier and water permeation

Water

Carbon nanotube

GO layer

Mechanism of ultrafast water permeation

Nature 414, 188 (2001)

Science 335, 442 (2012)

Mechanism

Permeation of water and gas barrier

Science 342, 91-95 (2013)Science 342, 95-98 (2013)

Selective gas sieving

Gas can permeate through thin GO membrane.

Thickness1.8～18 nm

Thickness3～7 nm

Spin-coat Vacuum filtration

Thickness 3-7 nm Thickness 9 nm

Science 342, 91-95 (2013) Science 342, 95-98 (2013)

Method

Thickness

Mechanism

Selective gas sieving

Heat

• Defect generation• Decrease of layer distance

Gases permeate through defects but not interlayer

Science 342, 91-95 (2013)

Science 342, 95-98 (2013)

MgCl2 solution Water

GO membrane(Thickness 1 μm)

Selective ion sieving Science 343, 752 (2014)

Permeation rates do not exhibit any notable dependence on ion charge.

The small species permeate with approximately the same speed.

Species larger than ～4.5 Å are sieved out.

Selective ion sieving

<4.5 Å

Selective ion sieving

Simulation and mechanism 7 Å

9 Å

13 Å

< 4.7 Å

< 5.8 Å

Wateronly

Conclusions

• Porous graphene showed gas and ion selectivity.

• Thick GO membrane showed high gas barrier property.

• GO membrane showed unimpeded permeation of water.

• Thin GO membrane showed high gas selectivity with maintenance of

high gas flow.

• GO membrane act as molecular sieves, blocking ions with hydrated

radii larger than 4.5 Å.

Thank you for your kind attention!

Nano Lett. 12 (7), 3602 (2012)Water desalination

Cl-Na+

Cl-Na+

Pore size < 23.1 Å Pore size < 16.3 Å

2～3 order

Science 335, 442 (2012) Nano Lett. 13 (8), 3930 (2013)

Permeation of water and gas barrier

Simulation

Spin-coat Vacuum filtration

3-7 nm 18 nm

Science 342, 91-95 (2013) Science 342, 95-98 (2013)

Selective gas sieving

Method

Thickness