Observation of oxo-bridged yttrium in TiO2 nanostructures and their enhanced photocatalytic hydrogen generation under UV/Visible light irradiations

Abstract Yttrium doped TiO2 (Y:TiO2) nanoparticles (NPs) and nanorods (NRs) are synthesized using facile wet chemical methods. Interestingly, the doped Y ions are found to be oxo-bridged with the host TiO2 through Y-O-Ti like formation as confirmed from their XRD and XPS studies. The photocatalytic hydrogen production efficiency of the synthesized nanostructures was studied under UV and visible light irradiations. The NPs of Y:TiO2 showed increased activity as compared to NRs. The observed efficiency of NPs is attributed to their three-dimensional confinement, where it facilitated a stronger oxo-bridging formation that improved the metal-to-metal charge transfer process, reducing the band gap and surface energies as compared to NRs. As investigated in this study, the oxo-bridging formation in the doped metal-oxide systems is relatively promising as this configuration largely favors the photocatalytic process by re-designing the charge separation and transfer processes as compare to the other conventional systems.