Preparation of Ag nanoparticles on nano cobalt-based metal organic framework (ZIF-67) as catalyst support for electrochemical determination of hydrazine

The present study introduced a novel, high performance and low-cost sensor in alkaline medium based on cobalt-based zeolitic imidazolate framework (ZIF-67). ZIF-67 nanocrystals with rhombododecahedral shape and large surface area were synthesized at room temperature and characterized via several techniques, i.e. field emission scanning electronic microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FT-IR) and thermogravimetric analyzer (TGA). Afterwards, ZIF-67 modified carbon paste electrode (ZIF-67/CPE) was prepared. Ag nanoparticles were formed on porous support (ZIF-67/CPE) through reduction of Ag ions in constant potential (Ag/ZIF-67/CPE). The electrochemical performance of the developed sensor was examined through cyclic voltammetry, amperometric technique and electrochemical impedance spectroscopy. The amperometric results represented good electro-catalytic activity of sensor for measurement of hydrazine with two linear ranges, from 4 to 326 µM and 326 to 4700 µM and detection limit (S/N = 3) of 1.45 µM. Ag/ZIF-67/CPE as a promising sensor showed good reproducibility, high selectivity and low response time to hydrazine detection in the presence of some potential interfering compounds. Furthermore, it was successfully utilized for determination of hydrazine in various water samples, with satisfactory recoveries. This work can open a new window for the application of MOFs as a platform to evaluate the target analytes.