In the presented work, we would like to present a new concept of a 2D solid solvent. This is a material, capable of selective ion or molecules capturing thanks to its developed surface, which is treated as a deposited on a substrate (usually spherical nano-silica or mesoporous silica) 2D bi- or multi-component layer. The latter one consists out of two main components – active anchoring units and passive spacers that are surface analogues of solute and solvent in an ordinary solution. The role of spacer units in this system is to separate active anchoring units to avoid their self-interactions and to create the required environment or ensure hydrophobicity/hydrophilicity of the entire system. The role of anchoring molecules, in turn, is to capture ions or molecules via the corresponding reactions, which can be treated as analogues of the occupation of free cites in the interstitial solid solutions. Whereas silica substrate, anchoring units and spacers are connected and act cooperatively for one final goal we consider to describe them as one part – solid solvent.

This class of material has great applicative potential in such areas as nanophotonics, electronics, catalysis and medicine, to name a few. In our work, we will clarify a definition of solid solvents as well as show some examples of them and their properties.