Tunable gas adsorption in graphene oxide framework

摘要

Effect of length of linker inter-space was studied on the adsorption capacity of CO2 by graphene oxide framework (GOF). Effect of linker inter-space of 14, 11, and 8 A was studied here. The linker interspace of 11 A showed the highest CO2 adsorption capacity. A dual-site Langmuir model was observed for adsorption of CO2 and CH4 into the GOF. According to radial distribution function (RDF), facial and central atoms of linker are the dual-site predicted by Langmuir model. Two distinguishable sites of adsorption and parallel orientation of CO2 are the main reasons of high adsorption capacity in 11 A linker inter-space. Gas-adsorbent affinity obtains the orientation of CO2 near the linker. The affinity in the 11 A linker inter-space is the highest. Thus, it forces the CO2 to lay parallel and orient more localized than the other GOFs. In addition, CH4 resulted higher working capacity than CO2 in 14 A. This occurs because of the change in gas-adsorbent affinity by changing pressure. An entrance adsorption occurs out of the pore of the GOF. This adsorption is not as stable as deep adsorption. (C) 2018 Elsevier B.V. All rights reserved.