Electrochemical conversion of Ni(OH)2 nanoparticle film into nickel hexacyanoferrate through a simple strategy of potential cycling

Electrochemical conversion of metal hexacyanoferrates into their oxides or hydroxides was successfully achieved and reported using nickel hexacyanoferrates (Ni-HCF). Herein, a versatile strategy for such a conversion was explored by potential cycling Ni(OH)2 nanoparticle film modified electrodes in K3[Fe(CN)6] or K4[Fe(CN)6] solution. The results show that K3[Fe(CN)6] is more prone to the conversion from Ni(OH)2 to Ni-HCF. Their composition, morphology, and structure were characterized by the techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and UV–vis spectrometry. The reaction mechanism is tentatively given. This strategy is also suitable for the other metal hydroxides including rare earth hydroxides such as neodymium, samarium etc.

► Electrochemical conversion of metal hexacyanoferrates into their hydroxides.
► K3[Fe(CN)6] being more prone to the conversion from Ni(OH)2 to Ni-HCF.
► Electrochemical conversion strategy suitable for the other metal hydroxides.