Clearly, the development of more efficient, cost-effective, and industrially-viable CO2 capture materials is essential for the deployment of large-scale CCS. Novel concepts for porous hosts used for CO2 capture and separation require a molecular level of control that can take advantage of differences in the chemical reactivity of gas molecules. A challenge in the capture of CO2 is tuning the selectivity of adsorbents, and coupled with this is the need to examine the adsorption selectivity at the molecular level. Neutron scattering has made important contributions in the understanding of the fundamental separation and storage mechanisms underpinning the functionality of porous materials used in CO2 capture processes. Great potential exists to develop porous hosts for this purpose using neutron scattering by probing adsorption sites, as well as guest orientation, dynamics, and diffusion in wide range of porous materials. Additionally, the characterization of the hosts themselves and their response to guest adsorption, both on a crystallographic and large-scale structure scale is important.

Postcombustion capture from power-plant flue streams provides one strategy towards reducing CO2 emissions to the atmosphere, however, there is an urgent need for new methods and materials that perform this separation. In contrast to the low pressure, predominantly CO2/N2 separation required for postcombustion capture, materials for precombustion (high pressure, predominantly CO2/H2) capture and natural-gas sweetening (predominantly CO2/CH4), have distinct requirements. Careful consideration must therefore be afforded to the working conditions of the material at which capture occurs in order to tailor the properties of that material. Commensurate with this requirement is the need for studying materials under rele­vant working conditions, with an emerging area of particular relevance being the understanding of gas transport in mixed gas and vapour streams. Such co-adsorption experiments, performed for CO2 and CH4 mixtures [88, 89], could be extended to study important ternary mixtures such as CO2/H2O/N2. This would allow derivation of important competitive gas-sorption mechanisms that are difficult to derive using other methods such as sorption analysis and diffuse-reflectance Fourier-transform infrared spectroscopy. This approach can be expanded further to include mixtures representative of separations that are industrially relevant, and for conversion and catalytic reactions.