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.