Investigation of CuO/ITO Photoelectrode Fabricated by PVD for Efficient Photoelectrochemical Water Splitting and...

Hydrogen and renewable fuels were generated using cost-effective and efficient electrocatalysts for water splitting. In this work, a CuO-based photocathode is used for the water splitting to generate hydrogen energy by PVD technique. The XRD analysis reveals the deposition of CuO thin film on ITO substrates, which is monoclinic. The XRD and LSV analysis of CuO confirmed the type of semiconductor and observed to be P-type semiconductor. SEM study of CuO confirmed the shape, morphology to be a circular and regular shape. The grain size of deposited CuO thin film was found to be 18 nm. The absorption and transmission of CuO thin film were observed through UV spectroscopy analysis and were found to be better photocatalyst in visible range 415-425 nm. The transmittance of the prepared thin film was noted to be maximum 7.6% in the UV range (280-300 nm). The band gap was also measured employing the Tauc plot and found to be 2.98 eV, which is most favorable for water splitting application. FTIR study showed the stretching, vibration, and the functional group of the deposited CuO thin film; the broad band of stretching of Cu-O in monoclinic CuO was observed at the range of 500-700 cm^-1, and further peaks were also noted at the range of 1500-1600 cm^-1. The linear sweep voltammetry (LSV) of CuO thin film was calculated in the absence of solar spectra and the presence of solar spectra and observed to be enhanced in current under solar spectra. The solar light to hydrogen emission percentage (STH %) of CuO through LSV was observed to be 2.04% under solar spectra. The low Nyquist curve of blank ITO and CuO-coated ITO substrate via electrochemical impedance spectroscopy (EIS) analysis was observed, which confirmed the enhancement of EIS of CuO-coated ITO. The hydrogen generation rate was also calculated by electrochemical cell and observed to be 5325.21 mol g^-1 for 6 h.