The increase of atmospheric CO 2 concentration over past few decades has hazardous eff ect on environments. In this study,

few layers (7–9) graphene adsorbents, prepared by chemical and thermal reduction techniques, were investigated for CO 2

adsorption. The study showed the eff ect of graphene structures on CO 2 removal at three diff erent temperatures (0, 25, and

50 °C) and in pressure range of 0–5 bar . The diff erent preparation methods induced diff erence in graphene structure in terms

of no. of layers (7–9), interlayer spacing (0.351–0.381 nm), surface area (152–409 m 2 /g), average pore size (2.0–4.1 nm)

and pore volume (0.48–1.63 cm 3 /g) as well as concentration of surface functional groups (10–20% oxygen content), which

in turn aff ected the CO 2 uptake. The chemically reduced graphene with least layer separation and lowest oxygen content

showed highest surface area (409 m 2 /g) and highest CO 2 uptake of 3.48 mmol/g. The thermally reduced graphene samples

exhibited a fl uffi er structure with good layer separation, but smaller surface area and increased pore volume. At 0 °C and

5 bar, CO 2 adsorption capacity (mmol/g) of thermally reduced graphenes was in order of graphene (Ar) (1.21) < graphene

(air) (1.54) < graphene (H 2 ) (2.0). The highest heat of adsorption of 22.5 kJ/mol was observed for graphene (hydrazine) at

initial adsorption conditions.