Improved hydrogen evolution efficiency in water splitting with <scp>WO</scp>₃ thin film via physical vapor deposition

Abstract WO 3 has successfully been deposited on indium tin oxide (ITO) substrate via physical vapor deposition (PVD) technique, and X‐rays diffraction (XRD) confirmed the deposition of a thin layer that is orthorhombic. The XRD and linear sweep voltammetry (LSV) study of the WO 3 thin film confirmed the type of semiconductor and observed it to be an n‐type semiconductor. The scanning electron microscopy (SEM) study revealed the uniform and porous morphology of the thin film, and the particle size of WO 3 was measured to be 34 nm without annealing. Fourier transform infrared (FTIR) confirmed the functional group and particle vibration (stretching, compression) the broad band of stretching of WO 3 is monoclinic and observed to be in the range of 3200–3500 cm −1 . The W‐O‐W peak is noted in the range of 400–500 cm −1 , while the W‐O peak is recorded in the range of 700–900 cm −1 , and furthermore, minor peaks were also recorded in the range of 1400–1700 cm −1 . UV spectroscopy provided the absorbance of the solar spectrum in the UV and visible range beyond 400‐nm range of wavelength. The maximum absorbance was noted in the UV range (320 nm) and gradually decreases with the wavelength. The maximum percentage transmittance was noted at a wavelength in the 500‐nm range, which is 88.67%. The band gap of the deposited thin film was also confirmed via the Tauc plot and observed to be 3.26 eV. The Electrochemical impedance spectroscopy (EIS) small curve of WO 3 is evidence of the low impedance and large photocurrent. The maximum photocurrent confirmed from LSV measurement was noted to be 0.51% at 0.8 V, which is quite good for water‐splitting applications. The hydrogen generation of the thin film through photoelectrochemical (PEC) water splitting was observed and found to have an average rate of 1743.09 mol g −1 for 6 h.