A new approach for the synthesis of K+-free nickel hexacyanoferrate

A Ni, Al hydrotalcite-like compound (Htlc) has been proven an useful host material for an alternative synthesis of a K+-free mixed hexacyanoferrate Ni1.5FeIII(CN)6, which is very difficult to obtain in bulk. The first stage of the procedure consists in the intercalation of hexacyanoferrate(III) inside the Htlc structure. The intercalated Htlc has been treated with a NiNO3 solution. The obtained material has been characterized by XRD, XAS Raman and FT-IR spectroscopy. The voltammetric response of the compound obtained after the complete solubilization of the Htlc host shows a typical fingerprint of nickel hexacyanoferrate material with a very low level of potassium. Elemental analysis confirmed the absence of K+ and thus the occurrence of K+-free nickel hexacyanoferrate (14% yield).

Graphical abstractA new synthetic route is proposed to prepare a K+-free nickel hexacyanoferrate by using a Ni, Al LDH, intercalated with Fe(CN)63−, as host material. The different host–guest solubility allowed us to synthesize, with a quite good yield, a pure mixed hexacyanoferrate, which is very difficult to obtain. Elemental analysis and cyclic voltammetry confirmed the absence of K+.Figure optionsDownload full-size imageDownload as PowerPoint slide