Nanocomposites based on Hofmann-type structure NiII(pz)[NiII(CN)4] (pz = pyrazine) nanoparticles for reversible iodine capture

Abstract

Hybrid nanocomposites based on nanoparticles with the Hofmann-type structure Ni^II(pz)[Ni^II(CN)₄] (where pz = pyrazine) confined into mesoporous silica or porous glass pearls were synthesised by sequential coordination of the molecular precursors into the pores of the functionalized matrices. Infrared (IR) and UV/Visible (UV-Vis) spectroscopy, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM) reveal the presence of uniformly-sized spherical Ni^II(pz)[Ni^II(CN)₄] nanoparticles of 3–6 nm, which are homogeneously dispersed into the matrices. These nanocomposites are able to efficiently capture iodine from cyclohexane solutions with a maximum sorption capacity of 1.75 mmol per g of material. A particular emphasis is given on the mechanism of iodine sorption as well as on the sorption cycling ability of the materials.