New Zn-NiHCF Hybrid Electrochemically Formed on Glassy Carbon: Observation of Thin Layer Diffusion during Electro-Oxidation of Hydrazine

Electrochemical modification of electrodes with thin films of metal hexacyanoferrates (MHCF) enhances the interfacial properties such as electrocatalysis, electrochromism, and ion transport properties. Attempts to prepare hybrids of metal hexacyanoferrates along with Au nanoparticles or by substituting the structure of MHCF with another metal ion were reported from various research groups including us. In this work, we report modification of glassy carbon with a new single phase hybrid Zn-NiHCF (hexacyanoferrate prepared in the presence of Zn2+ and Ni2+) electrochemically for the first time. The hybrid film was characterized by a single well reversible redox process centered at 450 mV. The effect of the zinc and nickel ions in the deposition bath on the effectiveness of modification was studied in detail. The modified hybrid films were characterized by voltammetry, chronoamperometry, field emission scanning electron microscopy, X-ray diffractometry, etc. The modified films were used for the electro-oxidation of hydrazine. The deviation from the expected behavior of the hybrid porous films provides evidence for the thin layer mass transport prevailing in the film. Thin layer diffusion behavior in MHCF films for the electrocatalytic oxidation of hydrazine is reported for the first time. The electro-oxidation of hydrazine appears to take place on the glassy carbon (GC) surface. The need for caution in analyzing the electrocatalytic properties of MHCF interfaces is reiterated.