Tuning the thermal stability of copper(II) hexacyanoferrate(II) nanoparticles

It is well known that the physical properties of nanoparticles can be tuned by controlling synthetic factors such as pH, temperature, reactant ratio or type of stabiliser used. In this work, the reactant ratio is varied to produce batches of copper(II) hexacyanoferrate(II) (Cu-HCF) with different cyano decomposition temperatures. This is accomplished by controlling the number of Fe(CN)64− site vacancies throughout the structure. By reducing the number of vacancies and consequently the need for water to complete the structure, the thermal decomposition temperature of Cu-HCF can be increased. In addition to this, we also note that the guest ion similarly contributes to the decomposition temperature. By exchanging K+ with Cs+, an increased resistance to thermal decomposition is realised. As the incorporation of Cs+ ions into the structure does not alter the number of Fe(CN)64− site vacancies, this enhancement is attributed to a change in the geometry of the copper coordination sphere.