Novel anodic $WO_3-SeO_2-CuO$ photoelectrode operating under solar illumination for water-splitting applications

Anodic tungsten oxide-based materials were tested as photoanodes in photoelectrochemical (PEC) water-splitting experiments. For the first time, we present the effect of selenization on the morphology, composition, and PEC properties of $WO_{3}-W_{18}O_{49}$ and $WO_{3}-WSe_{2}$ materials. Additionally, these substrates underwent copper electrodeposition followed by re-annealing to form novel, highly efficient $WO_{3}-SeO_{2}-CuO$ composite photoelectrodes. A comprehensive investigation of their morphology, chemical composition, optical properties, and photoelectrochemical performance was conducted based on the data gathered from Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), Raman Spectroscopy (RS), X-ray Photoelectron Spectroscopy (XPS), UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS), Mott-Schottky analysis, and PEC experiments. Results showed that the heterojunction-based electrode exhibited two fold increase in the PEC response of the photoanode before modification with copper compounds and nearly seven times the response of $WO_{3}-CuO$ materials.