Anita Das, Deanna M. D’Alessandro and Vanessa K. Peterson

Abstract Solid porous materials represent one of the most promising technologies for separating and storing gases of importance in the generation and use of energy. Understanding the fundamental interaction of guest molecules such as carbon dioxide in porous hosts is crucial for progressing materials towards industrial use in post and pre combustion carbon-capture processes, as well as in natural-gas sweetening. Neutron scattering has played a significant role already in providing an understanding of the working mechanisms of these materials, which are still in their infancy for such applications. This chapter gives examples of insights into the working mechanisms of porous solid adsorbents gained by neutron scattering, such as the nature of the interaction of carbon dioxide and other guest molecules with the host as well as the host response. The synthesis of many of these porous hosts affords significant molecular-level engineering of solid architectures and chemical functionalities that in turn control gas selectivity. When directed by the insights gained through neutron-scattering measurements, these materials are leading toward ideal gas separation and storage properties.