A novel Z-scheme heterojunction g-C3N4/WS2@rGONR(x) nanocomposite for efficient photoelectrochemical water splitting

Abstract

In the present work, 2D monolayers of WS2 and g-C3N4 were synthesized for the preparation of WS2/g-C3N4 nanostructure through a two-step process. 1D graphene oxide nanoribbons (GONRs) were synthesized via unzipping of multi-walled carbon nanotubes (MWCNTs) and applied for the preparation of three-component g-C3N4/WS2@rGONR(x) (x = 1, 2, and 5 wt%) nanocomposites. The synthesized nanocomposites were evaluated via Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HRTEM), and diffuse reflectance spectroscopy (DRS). The photocatalytic performance of the nanostructures was investigated in the hydrogen evolution reaction (HER) using the Fluorine-doped tin oxide (FTO) as the electrode. Subsequently, a possible photocatalytic mechanism was estimated. According to the results, the g-C3N4/WS2@rGONR(x) modified FTO has the lowest Tafel slope (60 mV dec−1), and overpotential (150 mV), the highest current density (47 mA cm−2) and also the maximum stability (19 mA for 3000s). Therefore, g-C3N4/WS2@rGONR(2) photocatalyst can be a novel and efficient candidate for hydrogen production as a clean fuel.