ZnSe and CdS Co‐Sensitized TiO2 Nanorod Arrays as Photoanodes for Bias‐Free Solar Hydrogen Evolution

Abstract The efficient charge separation and surface state reactions are significant in enhancing the efficiency of photoelectrochemical hydrogen evolution. Herein, we report a ternary heterostructure consisting of CdS/ZnSe sensitized TiO 2 nanorod as a photoanode. The heterojunction photoanode considerably widens the photon absorption spectral range and thereby enhances the photocurrent density up to 2 mA/cm 2 at 1.23 V versus RHE which is 10 times higher than pristine TiO 2 photoanode. The photoelectrochemical results demonstrate a high photocurrent density of 2 mA/cm 2 with a photon‐to‐current conversion efficiency of 1.5 % at a very low applied bias (0.2 V vs RHE). The improved PEC performances of the multidimensional hybrid photoanode could be ascribed to the efficient visible‐light absorption of ZnSe and CdS nanocrystals decorated on the surface of 1D TiO 2 . The rapid electron‐transfer properties owing to higher carrier density, low carrier transport resistance, and an extended lifetime of photoexcited carriers in the multidimensional ZnSe/CdS/TiO 2 heterostructure with suppressed surface charge recombination are responsible for enhanced hydrogen evolution activities.