Synthesis, characterization and electrochemical evaluation of hydrogen storage capacity of graphitic carbon nitride and its nanocomposites in an alkaline environment

Abstract

Herein, synthesis of graphitic carbon nitride (g-C3N4) and its nanocomposites with monometallic nickel (Ni-g-C3N4), and bimetallic zirconium-nickel (ZrNi-g-C3N4) is reported. New materials for high storage performance are investigated eagerly in electrochemical energy applications. With this aim, the electrochemical method is used for the evaluation of hydrogen storage capacity (HSC) of the samples in the present research work. Synthesis of samples were carried out using a combination of thermal and hydrothermal methods. The evaluation of electrochemical hydrogen sorption and storage capability of g-C3N4 and its nanocomposites was done after sample characterization. Characterization techniques followed were powder X-ray diffraction (XRD), Nitrogen adsorption and desorption isotherms measurements at 77 K, thermo-gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectrometry (EDS). Cyclic voltammetric and chronopotentiometry measurements carried out in an alkaline medium helped to calculate the HSC. The discharge capacity was measured to be 82 mAhg−1 for g-C3N4, 182 mAhg−1 for Ni-g-C3N4 and 380 mAhg−1 for ZrNi-g-C3N4 at 1 mAg−1 of current density. Catalytic properties of the metal nanoparticles augment the storage capability of the g-C3N4 nanocomposites. These nanocomposites help to store hydrogen which serves as safe carrier in fuel cell applications.