توسعه اتصالات ناهم ‌ساختار g-C3N4/ZnO به روش‌های پس عملیات روی پوشش‌های فتوکاتالیستی متخلخل دی‌اکسید تیتانیم به‌منظور تشکیل فتوکاتالیست‌های فعال تخت نوشDevelopment of g-C3N4/ZnO Heterojunctions via Post-Treatment (Hydrothermal) Methods on Porous TiO2 Photocatalytic Coatings for Visible-Light-Active Photocatalystsر مرئی

نوع: Type: Thesis

مقطع: Segment: masters

عنوان: Title: توسعه اتصالات ناهم ‌ساختار g-C3N4/ZnO به روش‌های پس عملیات روی پوشش‌های فتوکاتالیستی متخلخل دی‌اکسید تیتانیم به‌منظور تشکیل فتوکاتالیست‌های فعال تخت نوشDevelopment of g-C3N4/ZnO Heterojunctions via Post-Treatment (Hydrothermal) Methods on Porous TiO2 Photocatalytic Coatings for Visible-Light-Active Photocatalystsر مرئی

ارائه دهنده: Provider: Shima Sheikhi

اساتید راهنما: Supervisors: (Arash Fattah-Alhosseini (Ph. D

اساتید مشاور: Advisory Professors: Minoo Karbasi (PH. D) & Payam Veisi (PH. D)

اساتید ممتحن یا داور: Examining professors or referees: (PH. D) Omid Imantalab (PH. D) & mazdak Izadi

زمان و تاریخ ارائه: Time and date of presentation: 2026

مکان ارائه: Place of presentation: سالن کنفرانس

چکیده: Abstract: Abstract: Due to the global crisis of water resource pollution caused by persistent organic pollutants, the development of high-efficiency heterogeneous photocatalytic systems active under visible light irradiation is of paramount importance. Titanium dioxide (TiO2) is a well-known photocatalyst owing to its chemical stability, non-toxicity, and low cost; however, its wide bandgap and rapid recombination rate of photogenerated electron-hole pairs limit its solar energy utilization. To address these limitations, a novel ternary heterogeneous photocatalyst based on g−C3N4/ZnO/TiO2 was designed and developed. First, porous titanium dioxide coatings were synthesized on commercially pure titanium substrates using the Plasma Electrolytic Oxidation (PEO) method. Subsequently, zinc oxide (ZnO) nanostructures with controlled morphologies, along with graphitic carbon nitride (g−C3N4) nanosheets, were deposited onto the porous TiO2 support via a hydrothermal post-treatment process. In this regard, various heterostructures with zero-dimensional/two-dimensional (0D-2D), one-dimensional/two-dimensional (1D-2D), and two-dimensional/two-dimensional (2D-2D) geometric configurations were synthesized and systematically compared. X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (SEM) analyses confirmed the uniform phase structure and successful immobilization of the components onto the porous PEO-derived substrate. Furthermore, Diffuse Reflectance Spectroscopy (DRS) and electrochemical characterizations, including Mott-Schottky plots and Electrochemical Impedance Spectroscopy (EIS), revealed that the coupling of these semiconductors established appropriate heterojunctions, which led to a reduction in charge transfer resistance at the interfaces, a significant enhancement in charge carrier separation, and their efficient transport. Evaluating the photocatalytic activity of the samples for the degradation of methylene blue (MB) under visible light irradiation demonstrated that the 2D-2D sample, due to its higher specific surface area and more uniform distribution of active sites, exhibited outstanding efficiency compared to the other structures. The findings of this study offer an effective approach for designing stable, high-performance, and easily recoverable photocatalytic coatings for practical water treatment applications.