Structural Investigation of NaNO₃ Nanophase Confined in Porous Silica

Abstract

We have demonstrated that thermal and vibrational investigations of sodium nitrate (NaNO3) physically confined in the porous silica hosts is an effective approach to mimic the solute clustering effects in aqueous solution. The results show that the structure of the NaNO3 confined in nanopores can be divided into three regions, i.e., the regular solid phase region, solution-like molecular aggregates region, and a new solid-like phase region. Depending upon the pore size of the porous host, the physical range of the three regions varies accordingly. For pore size d <2.5 nm, only the solution-like molecular aggregates phase remains.