Photoelectrochemical application of WS2 nanosheets prepared via a low-temperature CVD method

Abstract

We report the low-temperature preparation of WS2 nanosheets by chemical vapor deposition (CVD) method for photoelectrochemical (PEC) water splitting application. The WS2 nanosheets were synthesized onto the FTO, ITO, SiO2, and glass substrates at a relatively low temperature of 500 °C under pressure of 10−2 Torr. Compared to temperatures of conventional WS2 synthesis via CVD method, the deposition was performed at a sufficiently low temperature, which has not been reported for the layer deposition yet. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet–visible (UV–visible) spectroscopy. The results show that WS2 nanosheets were grown almost vertically and alike a single crystal. Based on the SEM images, the WS2 nanosheets grew homogenously on the FTO substrate and covered the entire surface of the substrate. Linear sweep voltammetry (LSV), applied bias photon to current efficiency (ABPE), photocurrent response, and electrochemical impedance spectroscopy (EIS) of the fabricated nanosheets were measured for the photoelectrochemical response. Because of no transferring to damage layer, the results showed that WS2 nanosheets on FTO substrate had good photoelectrochemical activity. The measured photocurrent of 32 µAcm−2 and ABPE efficiency of 0.84% at a 0.75 V bias (versus RHE) was considerably high compared to the other results reported for WS2 nanosheets.