Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study
A series of Er-, Yb-, Ho-, Tb-, Gd-, Pr-TiO2 nanotubes (RE-NTs) was prepared via an electrochemical method. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis absorption, scanning electron microscopy (SEM) and luminescent spectroscopy. The experiments demonstrated that toluene in the gas phase was successfully degraded under visible light (LEDs λmax = 465 nm) using RE-NTs. In the presence of the most active sample (Ho-NTs), the photodegradation of toluene reached 30% after 60 min of vis irradiation. To investigate the localization of RE in the TiO2 structure, computer simulations were performed using the plane-wave-based Vienna ab-initio simulation package (VASP) implementing spin-polarized density-functional theory (DFT) and the generalized gradient approximation (GGA). It is proposed that during the electrochemical process, TiO2 systems with new Ho-f states below the conduction band of TiO2 is formed. The photocatalytic activity under Vis irradiation is attributable not to radical dotOH but to other forms of reactive oxygen species (O2radical dot−, HO2radical dot, H2O2).
Paweł Mazierski, Wojciech Lisowski, Tomasz Grzyb, Michał Jerzy Winiarski, Tomasz Klimczuk, Alicja Mikołajczyk, Jakub Flisikowski, Adam Hirsch, Agnieszka Kołakowska, Tomasz Puzyn, Adriana Zaleska-Medynska, Joanna Nadolna. (2017). Enhanced photocatalytic properties of lanthanide-TiO2 nanotubes: An experimental and theoretical study, 205, 376-385. https://doi.org/10.1016/j.apcatb.2016.12.044
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