Electrochemical hydrogen storage of synthesized heterostructure of hexagonal boron nitride-carbon nano tube

Abstract

Hexagonal boron nitride (h-BN), also known as white graphene, is attracting much attention as a two-dimensional material, and its applications are developed in diverse fields. In this study, the h-BN particles were utilized as a dopant on the surface of the carbon nanotubes (CNTs), to form a heterostructure, synthesized by hydrothermal method at 200 °C for 24 h. Three different amounts (30, 40, and 70 vol%) of h-BN were used. The peak shift and appearance of the nitrogen peak in the results of Fourier transform infrared (FT-IR) and Raman spectra indicated the successful synthesis of the nanostructure of h-BN/CNT. The scanning electron microscopy was carried out to study the morphology and microstructure of achieved heterostructure. To evaluate the electrochemical hydrogen storage capacity, the layer of the h-BN/CNT nanostructure was applied to the porous nickel foam through dip coating within 15 min, and then electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostat charge/discharge (GDC) at a KOH 6 M solution at room temperature were carried out. Results showed that with the doping of h-BN, the hydrogen adsorption capacity of the CNT was enhanced due to changes in the morphology of h-BN particles from flake-shape to the spherical and as a result, increasing the active sites of hydrogen adsorption on the surface of the CNT. The maximum specific capacity was achieved 1150 mA h/g for sample with 30 vol% of h-BN.