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Functional Materials for Energy

Local structures ‒ key to improved gas adsorption in carbon materials


(Inset, top left) A simulated disordered carbon structure. (Inset, bottom right) Same structure, with dense colored regions showing the strongest adsorption positions. (Main figure) Isosteric heat of adsorption as a function of carbon density, showing the strong change of adsorption with pore size.

Combined results from electron microscopy, neutron scattering, and theory, illustrate the link between local structures and adsorption properties in carbon materials.  The achieved understanding at the atomic scale is a crucial step towards predicting and designing materials with enhanced gas adsorption properties, with important implications for applications such as energy storage and carbon capture.

A recent feature article discusses quantitative structure-function links in nanoporous carbons. Scanning transmission electron microscopy studies show that there is significantly higher structural order than generally expected in nanoporous carbons. Small angle neutron scattering probes the distribution of absorbed gas molecules at smaller length scales than previously possible. Atomic-level calculations demonstrate that local defects observed by microscopy provide stronger gas binding, and predict the superdensification of adsorbates in pores of optimal size, in agreement with observations from in situ neutron scattering. Together, these techniques can lead to new design concepts for building novel nanoporous materials with tailored properties, and predictive techniques for screening materials for specific properties.

J. R. Morris, C. I. Contescu, M. F. Chisholm, V. R. Cooper, J. Guo, L. He, Y. Ihm, E. Mamontov, Y. B. Melnichenko, R. Olsen, S. J. Pennycook, M. Stone, H. Zhang, and N. C. Gallego, “Modern approaches to studying gas adsorption in nanoporous carbons,”  J. Mater. Chem. A 1, 9341 (2013). http://dx.doi.org/10.1039/C3TA10701A

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