Molecule-based cobalt hexacyanoferrate nanoparticle: Synthesis, characterization, and its electrochemical properties

Cobalt hexacyanoferrate (CoHCF) nanoparticles, with an average size of less than 50 nm for individual crystallite, were synthesized by simply mixing appropriate reactants in the absence of surfactant or template. Elemental analysis provided a stoichiometric formula, K_0.2Co _1.4[Fe(CN)₆]·xH₂O for this compound. The involvement of both ferromagnetic Co_1.5^II [Fe ^III(CN)₆] and antiferromagnetic KCo^III[Fe ^II(CN)₆] species in the CoHCF complex was effectively proved by Fourier transform infrared spectroscopy, so was the existence of certain amounts of interstitial water molecules. A glassy carbon electrode modified with these CoHCF nanoparticles had high stable and reversible cyclic voltammetric responses even at high scan rates and its electrochemical properties were affected by the nature of counter cations and the concentration of supporting electrolyte. The prepared nanoparticle films, as a mediator on electrode surface, exhibited considerable electrocatalytic activity toward the oxidation of dopamine.