Influence of surface chemistry on the SAXS response of polymer-based activated carbons

Distorted Graphene Sheet Structure-Derived Latent Nanoporosity

High surface area graphene monoliths consist mainly of single graphene layers wider than 10 nm. The interlayer porosity of high temperature treated nanoporous graphene monoliths with tuned intergraphene layer structures is evaluated by hybrid analysis of Ar adsorption at 87 K, N2 adsorption at 77 K, high resolution transmission electron microscopic observation, and small-angle X-ray scattering (SAXS) measurements. SAXS analysis results in surface areas that are 1.4 and 4.5 times larger than those evaluated by Ar adsorption for graphene monoliths nontreated and treated at 2273 K, respectively. A distorted graphene sheet structure model is proposed for the high surface area graphene monoliths on the basis of the hybrid analysis.

Carbide-derived carbons: a comparative study of porosity based on small-angle scattering and adsorption isotherms

Porous carbons have received much attention recently for potential applications in energy generation and storage, molecular sieving, and environmental remediation. Property optimization for specific applications rests largely on controlling the volume, size, and shape of the pores at the synthetic level. Direct atom-scale experiments which might accurately and reliably measure these quantities are problematic, so indirect methods such as gas sorption are generally employed. Here we apply a second indirect method, small-angle X-ray scattering (SAXS), to study porosity in carbide-derived carbons (CDC). The results qualitatively confirm and reinforce model-dependent conclusions drawn from gas sorption isotherms. In particular, both techniques indicate the onset of broad polydispersity under the same processing conditions for particular porous carbon materials.