Surface modification of highly ordered TiO2 nanotube arrays for efficient photoelectrocatalytic water splitting

An efficient visible-light-sensitive heterostructure photoanode of CdS nanoparticles/ZnO shell/TiO2 nanotube (CdS/ZnO-TiNT) arrays were investigated for solar water splitting. Highly ordered arrays of TiNT were grown vertically on Ti foil by electrochemical anodization. Both aqueous solution routes were used in turn to coat a thin recombination barrier of ZnO shell and narrow band gap CdS nanoparticles to the surface of the TiNT arrays. As a result of strong absorption within solar spectrum and effective suppression of electron-hole pair recombination in CdS/ZnO-TiNT arrays, a significant improvement in solar-to-hydrogen conversion efficiency from 0.39% to 1.30% was obtained.