Ultrasonic-assisted synthesis of nickel metal-organic framework for efficient urea removal and water splitting applications

Abstract

The change in the climate is considered a critical environmental issue that humanity will deal with through the next decade. Herein, the ultrasonic-assisted method prepared the metal-organic framework for several environmental applications. The Ni-MOF was used as an efficient electrocatalyst for electrochemical urea removal. The prepared materials were characterized by analytical techniques like powder infrared spectroscopy, X-Ray diffraction, scanning electron microscopy, and Brunauer-Emmett-Teller surface area analysis. Several electrochemical techniques were used to study the activity of Ni-MOF toward urea removals, like cyclic voltammetry, linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. The activity of the modified GC/Ni-MOF electrode toward urea oxidation was expressed as a function of current density. Thus, the current density value reached 64 mA cm−2 at a potential of 0.41 V (vs. Ag/AgCl). Many kinetic parameters were studied, like diffusion coefficient (D), surface coverage (Γ), Tafel slope, and charge transfer coefficient (α). Else, the activity of the electrode was investigated toward water splitting. The oxygen evolution was studied in an alkaline medium. Accordingly, the electrode recorded 50 mA cm−2 at the potential of 0.76 and 0.85 V (vs. Ag/AgCl) for GC/Ni-MOF and GC/NiO, respectively.