Marked adsorption irreversibility of graphitic nanoribbons for CO ₂ and H ₂O

Graphene and graphitic nanoribbons possess different types of carbon hybridizations exhibiting different chemical activity. In particular, the basal plane of the honeycomb lattice of nanoribbons consisting of sp ²-hybridized carbon atoms is chemically inert. Interestingly, their bare edges could be more reactive as a result of the presence of extra unpaired electrons, and for multilayer graphene nanoribbons, the presence of terraces and ripples could introduce additional chemical activity. In this study, a remarkable irreversibility in adsorption of CO ₂ and H ₂O on graphitic nanoribbons was observed at ambient temperature, which is distinctly different from the behavior of nanoporous carbon and carbon blacks. We also noted that N ₂ molecules strongly interact with the basal planes at 77 K in comparison with edges. The irreversible adsorptions of both CO ₂ and H ₂O are due to the large number of sp ³-hybridized carbon atoms located at the edges. The observed irreversible adsorptivity of the edge surfaces of graphitic nanoribbons for CO ₂ and H ₂O indicates a high potential in the fabrication of novel types of catalysts and highly selective gas sensors.