A PN-type CuO@TiO2 nanorods heterojunction for efficient PEC water splitting: DFT model and experimental investigation on the effect of calcination temperature

Abstract

Heterojunction formation between two dissimilar semiconductors is a promising strategy to improve the harvesting of the visible photons and separation of the electron-hole pairs in semiconductor-based photocatalysts. Herein, the interfacial characteristics of TiO2 rutile (011) surface and Cu-MOF derived cupric oxide (CuO) were examined via simulation and experimental approaches for solar hydrogen production. The results illustrate the formation of van der Waals type heterojunction (Type-II) with higher visible light absorption and lesser charge transfer resistance. This was attributed to significant charge transfer from CuO to the TiO2 surface, establishing a PN-type heterojunction. The valence band maxima and conduction band minima of the designed heterostructure matched well with redox potential of water even with the considerable bandgap reduction around 1.66 eV. Furthermore, the hybrid photocatalyst calcined at 450 °C produced the highest hydrogen production at 32,766 μmol g−1 h−1. The outcome thus provides a valuable insight in developing suitable photocatalysts for practical production of hydrogen through photo-electrolysis technique.