Doped titanium dioxide for the photocatalytic degradation of herbicides
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Auditorium IT115, Linnanmaa campus
Topic of the dissertation
Doped titanium dioxide for the photocatalytic degradation of herbicides
Doctoral candidate
Master of Science Jennyffer Stefanía Martínez Quimbayo
Faculty and unit
University of Oulu Graduate School, Faculty of Technology, Environmental and Chemical Engineering Research Unit
Subject of study
Environmental Engineering
Opponent
Associate Professor Cláudia Gomes Silva, University of Porto
Custos
Associate Professor Satu Ojala, University of Oulu
Doped titanium dioxide for the photocatalytic degradation of herbicides
This thesis investigates the development of mono and bimetallic TiO2 based photocatalysts for the degradation of emerging pollutants in water, with a focus on Diuron (DIU) and Atrazine (ATZ). Although TiO2 is widely recognized as an effective photocatalyst, its practical application is limited by poor visible light activity due to its wide band gap. To address this limitation, metal impregnation with Rh, Pt, and combined Rh/Pt systems was explored.
The catalysts were synthesized using wet-impregnation and co-impregnation methods and characterized by XRD, TEM, BET, UV-Vis, PL, and XPS. In addition, Density Functional Theory (DFT) calculations and kinetic modelling were employed to understand electronic structure modifications and reaction mechanisms. The results show that metal incorporation introduces new electronic states within the band gap and improves charge carrier dynamics. Monometallic and bimetallic impregnation contributed to band structure modification and visible light activation.
Photocatalytic performance was found to depend on pollutant structure and reaction conditions. DIU was efficiently degraded, whereas ATZ showed lower degradation due to its higher stability. In mixed systems, competitive effects decreased overall efficiency. Scavenger experiment indicated that h+ and O2•- are the main reactive species responsible for DIU degradation.
Compared to the literature the catalysts developed in this work exhibit competitive performance under visible light and at lower catalyst loadings, highlighting their potential for energy efficient water treatment. Overall, this thesis established structure-property-performance relationships that support the rational design of advanced photocatalysts for the removal of emerging pollutants.
The catalysts were synthesized using wet-impregnation and co-impregnation methods and characterized by XRD, TEM, BET, UV-Vis, PL, and XPS. In addition, Density Functional Theory (DFT) calculations and kinetic modelling were employed to understand electronic structure modifications and reaction mechanisms. The results show that metal incorporation introduces new electronic states within the band gap and improves charge carrier dynamics. Monometallic and bimetallic impregnation contributed to band structure modification and visible light activation.
Photocatalytic performance was found to depend on pollutant structure and reaction conditions. DIU was efficiently degraded, whereas ATZ showed lower degradation due to its higher stability. In mixed systems, competitive effects decreased overall efficiency. Scavenger experiment indicated that h+ and O2•- are the main reactive species responsible for DIU degradation.
Compared to the literature the catalysts developed in this work exhibit competitive performance under visible light and at lower catalyst loadings, highlighting their potential for energy efficient water treatment. Overall, this thesis established structure-property-performance relationships that support the rational design of advanced photocatalysts for the removal of emerging pollutants.
Created 27.8.2026 | Updated 28.8.2026