Graphene oxide-derived porous materials for hydrogen/methane storage and carbon capture

Abstract

© 2016 by Taylor & Francis Group, LLC. Nanoporous solids with high accessible specific surface area and pore volume, high chemical and mechanical stability are considered as one of the key materials to solve many energy and environment-related problems. Abundant porous carbon materials have attracted great attention in hydrogen/meth-ane storage, and carbon capture. Graphene-based materials are relatively new members of the carbon family and opened up great scope for molecular sorption, storage and separa tion due to the flexibility in designing functionalized surfaces and tuneable porosities. In this chapter, we describe recent research efforts to synthesize a variety of graphene-based structures, starting with layered, expanded graphite, interca lation, exfoliation, chemical reduction, pillaring layers, self assembly, surface functionalization, doping, metal dispersion, porous template, chemical activation, and hierarchical pore structures for hydrogen/methane storage and carbon capture. Graphene oxide (GO, also known as graphite/graphitic oxide) was first prepared by Brodie (1859). It is an oxidized graphite compound, with a nominal C:O ratio between 2 and 3, usually obtained by treating graphite with strong oxidizers: Mixtures of nitric/sulfuric acid, sodium nitrate, and potassium/chlo-rate/permanganate (Dreyer et al. 2010, 2012; Hummers and Offeman 1958). Structurally, GO is a layered structure with an interlayer spacing of about 0.7 nm, twice that of graphite (Barroso-Bujans et al. 2010; Burress et al. 2010; Dreyer et al. 2010). The GO structure contains abundant oxygen-rich func tional groups: Hydroxide and epoxide groups on basal planes, and carbonyl and carboxyl groups on the edges of graphene sheets. This makes GO hydrophilic in nature and soluble in water and several solvents (Dreyer et al. 2010). GO with its lamellar water, a largely expanded and tunable layered struc ture provides a rich platform for a wide range of functional ity and reaction sites for chemical modifications. Thus, GO becomes a more popular and versatile precursor for the syn thesis of large-scale graphene-related materials (Aboutalebi et al. 2012; Chandra et al. 2012; Li and Shi 2012; Liu et al. 2013; Srinivas et al. 2010, 2011, 2012; Yang et al. 2013). A variety of GO-based porous network structures are discussed in this chapter, particularly for hydrogen/methane storage and carbon (dioxide) capture. These include simple, single- to few-layer randomly arranged graphenes through thermal exfoliation of GO, well-ordered and pillared layer structures of GO, and chemically activated GO, with tunable and functional pore structures and large internal surface area.