A novel non-precious catalyst containing transition metal in nanoporous cobalt based metal-organic framework (ZIF-67) for electrooxidation of methanol

In present work, Ni catalysts doped in zeolitic imidazolate framework (ZIF-67) as conductive support were used for electrocatalytic oxidation of methanol. For this purpose, the nanosized ZIF-67 crystals were synthesized using a straightforward non-template method. The as-synthesized nanocrystal was characterized using FE-SEM, TEM, XRD, FT-IR, TGA and BET. Then, a carbon paste electrode (CPE) was modified by ZIF-67 nanoparticles doped with Ni species (Ni-ZIF-67/CPE). Cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) were employed for methanol electrooxidation, The CV exhibited remarkable oxidation current due to the increase of Ni species doped porous ZIF-67 support. EIS data showed that the activation process increases the charge transfer rate and conductivity of modified electrode. Also, the value of rate constant of catalytic redox reaction was obtained using CA. As a result, the Ni species supported on ZIF-67/CPE showed significant catalytic activity and good stability toward methanol oxidation reaction (MOR) in comparison with non-modified CPE. This work can open a new window for application of various Metal-organic frameworks (MOFs)/platinum-free metals as electrocatalysts in fuel cells.