  Porous carbonaceous materials have many important industrial applications
including energy storage, water purification, and adsorption of volatile
organic compounds. Most of their applications rely upon the adsorption of
molecules or ions within the interior pore volume of the carbon particles.
Understanding the behaviour and properties of adsorbate species on the
molecular level is therefore key for optimising porous carbon materials, but
this is very challenging owing to the complexity of the disordered carbon
structure and the presence of multiple phases in the system. In recent years,
NMR spectroscopy has emerged as one of the few experimental techniques that can
resolve adsorbed species from those outside the pore network. Adsorbed, or
"in-pore" species give rise to resonances that appear at lower chemical shifts
compared to their free (or "ex-pore") counterparts. This shielding effect
arises primarily due to ring currents in the carbon structure in the presence
of a magnetic field, such that the observed chemical shift differences upon
adsorption are nucleus-independent to a first approximation. Theoretical
modelling has played an important role in rationalising and explaining these
experimental observations. Together, experiments and simulations have enabled a
large amount of information to be gained on the adsorption and diffusion of
adsorbed species, as well as on the structural and magnetic properties of the
porous carbon adsorbent. Here, we review the methodological developments and
applications of NMR spectroscopy and related modelling in this field, and
provide perspectives on possible future applications and research directions.
