Nano-composites based on Hofmann-type structure Ni(II)(pz)[Ni(II)(CN)₄] (pz = pyrazine) nanoparticles for reversible iodine capture

Hybrid nano-composites based on nanoparticles with the Hofmann-type structure Ni(II)(pz)[Ni(II)(CN)₄] (where pz = pyrazine) confined into meso-porous 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 nano-composites 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. (authors)