Study of Oxygen Vacancies in TiO2 Nanostructures and Their Relationship with Photocatalytic Activity

Applied Sciences

Aurelio Heredia Jiménez¹  Alba Arenas-Hernandez²  Carlos Roberto Ascencio-Hurtado²  Netzahualcoyotl Carlos²  Wilfrido Calleja Arriaga²  Carlos Zuñiga Islas²  Julio César Mendoza-Cervantes²  Mario Moreno² 

[1] Electronics Department, Popular Autonomous University of the State of Puebla (UPAEP), Puebla 72410, Mexico;National Institute of Astrophysics, Optics and Electronics (INAOE), Electronics, Tonantzintla, Puebla 72840, Mexico;

关键词: oxygen vacancies;    anatase;    photocatalytic activity;    TiO₂ nanosheets;    TiO₂ nanobowls;    TiO₂ nanotubes;   

DOI  :  10.3390/app12073690

来源: DOAJ

【 摘 要 】

In this research work, we present the synthesis and characterization of four different TiO₂ structures, such as nanotubes, nanocavities, nanosheets assembled on nanocavities and nanobowls assembled on nanocavities, prepared by electrochemical anodization using organic electrolytes. After synthesis, the structures were thermally annealed to pass from the amorphous phase to the anatase phase, which is one of the most important crystalline structures of TiO₂ due to its high photocatalytic activity and stability. The unique morphology and topography were studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The elemental composition was determined by energy-dispersive X-ray spectroscopy (EDS). The anatase phase was verified by Raman microscopy and X-ray diffraction (XRD), the band gap energy was calculated by the Kubelka–Munk function, and the main defect states that generate the emission, as well as their lifetime, were determined by photoluminescence spectroscopy and time response photoluminescence (TRPL), respectively. The TiO₂ nanomaterials were tested as catalysts in the photodegradation of a solution of methylene blue using a UV lamp at room temperature. The results showed complex morphologies and different surface roughness areas of these nanomaterials. Furthermore, a relationship between defect states, band gap energy, and photocatalytic activity was established. We found that the catalytic activity was improved as an effect of geometric parameters and oxygen vacancies.

【 授权许可】

Unknown