A novel photoelectrode from TiO₂-WO₃ nanoarrays grown on FTO for solar water splitting

TiO₂-WO₃ nanorod arrays were synthesized on fluorine-doped tin oxide (FTO) substrates via a template free process, hydrothermal procedure combined with electrodeposition. The designed photoelectrodes were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM) and photoelectrochemical measurements. These arrays are employed as photoanodes in water splitting systems under illumination of AM 1.5 G (110 mW/cm²). This study demonstrates that the WO₃ deposition interval time (0, 10, 20, 40, 60 min) can significantly affect the photoelectrochemical performance and the amount of hydrogen generated. The optimal deposition time was 20 min, which is sufficient to homogeneously coating the TiO₂ nanorods and enhance the photoconversion efficiency of TiO₂-WO₃ array by 60% compared to pure TiO₂ array. The enhanced electrode efficiency was attributed to efficient charge separation and reduction of the electron-hole pair recombination rate