Uptake of $H_2$ and $CO_2$ by graphene

Ghosh, Anupama and Subrahmanyam, KS and Krishna, Katia Sai and Datta, Sudipta and Govindaraj, A and Pati, Swapan K and Rao, CNR (2008) Uptake of $H_2$ and $CO_2$ by graphene. In: Journal of Physical Chemistry C, 112 (40). pp. 15704-15707.

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Abstract

Graphene samples prepared by the exfoliation of graphitic oxide and conversion of nanodiamond exhibit good hydrogen uptake at 1 atm, 77 K, the uptake going up to 1.7 wt %. The hydrogen uptake varies linearly with the surface area, and the extrapolated value of hydrogen uptake by single-layer graphene works out to be just above 3 wt %. The $H_2$ uptake at 100 atm and 298 K is found to be 3 wt % or more, suggesting thereby the single-layer graphene would exhibit much higher uptakes. Equally interestingly, the graphene samples prepared by us show high uptake of CO,,, the value reaching up to 35 wt % at I atm and 195 K. The first- principles calculations show that hydrogen molecules sit alternately in parallel and perpendicular orientation on the six-membered rings of the graphene. Up to 7.7 wt % of hydrogen can be accommodated on single-layered graphene. $CO_2$ molecules sit alternatively in a parallel fashion on the rings, giving use to a maximum uptake of 37.93 wt % in single-layer graphene. The presence of more than one layer of graphene in our samples causes a decrease in the $H_2$ uptake.

Item Type:	Journal Article
Publication:	Journal of Physical Chemistry C
Publisher:	AMER CHEMICAL SOC
Additional Information:	Copyright for this article belongs to American Chemical Society
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	26 Dec 2008 11:04
Last Modified:	19 Sep 2010 04:51
URI:	http://eprints.iisc.ac.in/id/eprint/16413

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