A novel ammonia complex-assisted ion-exchange strategy to fabricate heterostructured PdO/TiO₂ nanorods with enhanced photocatalytic activities

Heterojunctions have been often employed to improve the photocatalytic behavior of titania-based materials. Herein, we propose a novel strategy to fabricate PdO/TiO₂ heterostructured nanorods, as PdO was proved to be an efficient co-catalyst in photocatalytic reactions. Primarily, ammonia complex-assisted ion-exchange method was used to store Pd(II) ions in protonated titanate nanotubes, as which cannot be replaced by metallic cations via traditional route. Then, PdO/TiO₂ heterojunctions formed through calcination in air, as nanotubes dehydrated and shrank into nanorods. X-ray diffraction, Raman spectra, and X-ray photoelectron spectroscopy were used to demonstrate the formation of PdO component, and transmission electron microscopy was employed to prove the successful connection between TiO₂ nanorods and PdO nanoparticles. Moreover, inductive coupled plasma proved excellent compositional gradient of Pd(II) in the PdO/TiO₂ heterostructured nanorods. In the present work, the photocatalytic activities of PdO/TiO₂ heterostructured nanorods were investigated by decoloring several dyes under UV illumination. Our research revealed appropriate PdO loading (1.0 wt%) enhanced photocatalytic performance compared with bare TiO₂ nanorods, where PdO/TiO₂ heterojunctions were responsible for the prohibitive photogenerated carries recombination.