Three-Dimensional Lupinus-like TiO2 Nanorod@Sn3O4 Nanosheet Hierarchical Heterostructured Arrays as Photoanode for Enhanced Photoelectrochemical Performance

A novel photoelectrode of three-dimensional (3D) lupinus-like TiO2 nanorod@Sn3O4 nanosheet hierarchical heterostructured arrays (TiO2@Sn3O4 HHAs) on a transparent F-doped SnO2 glass substrate was designed and fabricated by a two-step solvothermal growth process. Photoelectrochemical (PEC) measurements showed that the 3D lupinus-like TiO2@Sn3O4 HHAs photoelectrode displayed enhanced photocurrent density (3-fold increase with respect to that of pure TiO2), improved conversion efficiency, more negative onset potential (from −0.13 to −0.33 V vs normal hydrogen electrode), and higher light on/off cycle stability. The improved PEC properties may be ascribable to the enhancement of light harvesting and large contact area with the electrolyte by increased surface area as well as improvement of charge transfer and collection through the synergistic effects between band structures and morphology.