Microwave irradiation: In-situ conversion of nanoflakes to nanoflowers of ZnCo2O4 on Ni foam for enhanced electro-catalytic activity

Spinel structure metal oxides provides the effective performance towards the electro-catalytic analysis. Among the spinel structure metal oxides, ZnCo2O4 has effective in the area of photocatalyst, gas sensor, li-ion batteries, supercapacitors (Qang et al.,) and electro-oxidation. The performance of direct methanol fuel cells hinges on the activity of the catalyst. To enhance the electro-catalytic activity, a flower-like nanostructure of ZnCo2O4 assembled on nickel foam (NF) via microwave irradiation process, the whole process was finished within 15 min [Sreekanth-2019]. The ZnCo2O4 nanoflower is successfully applied in the electro-catalytic oxidation of methanol and its electro-catalytic performance is investigated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy, which exhibits excellent electro-catalytic activities towards methanol electro-oxidation in alkaline medium, including low onset potential (0.45 V), high current densities (222.3 mA cm-2) at 0.70 V (vs. SCE), and desirable electro-oxidation stability (91%) after 500 cycles in the presence of 1.0 M KOH mixed with 0.5 M methanol (Jadhav et al.,). The electrochemical oxidation of MeOH was also observed at higher concentration of MeOH up-to 4.0 M (0.5, 1.0, 2.0, 3.0 and 4.0 moles). The high electrochemical performance is mainly attributed to faster ion/electron transfer and an enhanced electrochemical kinetics. The present simple, and cost-effective synthesis approach can open new era for large-scale applications of the novel materials for different electrochemical applications.