One-step hydrothermal synthesis of WS2 as efficient electrode material for energy storage application

Abstract

Transition metal dichalcogenides (TMDs) are a class of two-dimensional (2D) materials which has several applications in the domain of optoelectronic devices, catalyst, sensor, and energy storage devices. Tungsten disulfide (WS2) is one of the important TMD material exhibiting semiconducting and metallic nature in the 2H and 1T phases respectively. Herein, we report a one-step hydrothermally synthesized large-scale and low-cost WS2 nanomaterial. Further, we have performed material characterization using X-ray diffraction (XRD), field emission gun-scanning electron microscopy (FEG-SEM), and transmission electron microscopy (TEM) to check the crystallinity, surface morphology, and shape of the nanomaterial. The XRD data matches very well with the mixed-phase 1T @ 2H of WS2. Also, the formation of crystal planes can be clearly seen from the high-resolution transmission electron microscopy (HRTEM) image of the synthesized material. Further, the surface morphology of as-grown WS2 nanomaterial has been investigated by field emission gunscanning electron microscopy (FEG-SEM) which shows the nanosheet-like morphology. Moreover, Raman spectroscopy has been done to check the presence of vibrational modes of the synthesized WS2. The Raman peaks were observed at 348.15 cm-1(E1 2g) and 414.18 cm-1 (A1g) corresponding to the in-plane vibrational mode and out-of-plane vibrational mode of 2H WS2. In addition, Raman peaks corresponding to the 1T phase of WS2 have also been obtained. This rigorous study on WS2 nanomaterial suggests its usefulness in energy storage applications such as supercapacitors, photocatalysis, and electrochemical sensors.