Uptake of H₂ and CO₂ by Graphene

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 2 , the value reaching up to 35 wt % at 1 atm and 195 K. The firstprinciples 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 singlelayered 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.

Feasibility of CO2 adsorption by solid adsorbents: a review on low-temperature systems

“…The group of carbonaceous material-based adsorbents encompasses a large variety of materials that include activated carbon obtained from a range of materials, graphene, mesocarbon and carbon nanotubes (CNTs) (Ghosh et al 2008;Saha and Deng 2010). Almost all carbonaceous materials of sufficient strength, low organic volatile content and high in elementary carbon can be converted into CO 2 adsorbent (David and Kopac 2014).…”

A study of the synthetic methods and properties of graphenes

“…We have measured the surface properties of few-layer graphene samples prepared by different methods. The Brunauer, Emmett and Teller (BET) surface area was typically in the range of 270-1550 m 2 g −1 , approaching the value of single-layer graphene for some samples [34]. The surface area varies as EG > DG > EG-H > HG.…”

“…These high surface area samples might enable the storage of hydrogen. Hydrogen storage reaches 3 wt% at 100 bar and 300 K and the uptake varies linearly with the surface area [34]. Theoretical calculations show that SLG can accommodate up …”

Two-dimensional inorganic analogues of graphene: transition metal dichalcogenides

“…Mesoporous WS 2 , prepared using SBA-15 as the template, has a high surface area and exhibits a storage capacity of 805 mAh −1 g −1 at a current density of 100 mA g −1 [146]. Owing to its high surface area and chemical stability, graphene has been used as a commercial anode material [147,148]. Composites of TMDCs and graphene have been investigated extensively for Li-ion storage.…”