The CO2 Storage Capacity of the Intercalated Diaminoalkane Graphene Oxides: A Combination of Experimental and Simulation Studies

To study the effect of interlayer spacing of pillared graphene oxides (GOs) on CO2 uptake, we have obtained CO2 isotherms with respect to the interlayer distance of pillared graphene oxide by both experimental and simulation methods. Interlayer distances of GO were modulated by intercalation of three kinds of diaminoalkanes with a different number of carbon atoms (NH2(CH2) n NH2, n = 4, 8, and 12) as pillars. The intercalated GOs (IGOs) and their reduced products (RIGOs) are characterized using a variety of approaches such as X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and N2 adsorption. Gas adsorption performance shows that the CO2 uptake of IGOs and RIGOs decrease with the increase of the interlayer distance at low pressure, while at high pressure, the adsorption capacity of IGO-12 has a larger growth than those of both IGO-4 and IGO-8 and surpasses them at 30 bar. The contribution of the electrostatics to CO2 adsorption is larger than that of van der Waals force at low pressures, whereas for the high pressures, the adsorption is dominated by van der Waals force.