Merging Cation Exchange and Photocatalytic Charge Separation Efficiency in an Anatase/K2Ti4O9 Nanobelt Heterostructure for Metal Ions Fixation.

Abstract

Efficient collection and safe disposal of toxic metals ions from aqueous solutions is critical for applications in environmental remediation. Although extensive efforts have been devoted to the synthesis of functional TiO2 materials, photocatalytic reduction (photoreduction) of aqueous metal ions into solid metals remains a challenge. We designed a TiO2 nanoparticle-decorated layered titanate (K2Ti4O9) material that retained the cation exchange ability of K2Ti4O9 but also possessed the enhanced charge separation efficiency of K2Ti4O9. Combining cation exchange with enhanced charge separation efficiency results in a heterostructured material with remarkably high activity for the photoreduction of metal ions. Initially we demonstrated how the photocatalyst can efficiently reduce aqueous Ni2+ cations, whereas the benchmark TiO2-based P25 catalyst showed little to no activity. The resulting Ni-deposited heterostructure can then be used as a catalyst for visible light-induced photocatalytic H2 evolution in water.