Anodik spark oksitleme tekniği ile üretilen titanyum dioksit (TiO2) kaplamaların karakterizasyonu ve fotokatalitik özellikleri

Abstract

İleri oksidasyon teknolojilerinden biri olan fotokatalitik bozunma, organik kirleticilerin temizlenmesinde ve su arıtımında ümit verici yöntemlerden biri olmaya başlamıştır.  Fotokatalistler arasında en dikkat çekeni ise, yüksek fotoaktiviteye sahip, kararlı ve düşük maliyetli olan titanyum dioksit (TiO2) yarı iletken malzemesidir.  Bu çalışmada TiO2 kaplamalar, fosforik asit (H3PO4) içerikli elektrolit içerisinde saf titanyumun anodik spark oksitleme metodu ile anotlanması sonucu üretilmiştir.  Farklı elektrolit konsantrasyonlarının (0.25-2 M H3PO4) altık yüzeyinde oluşan TiO2’nin mikroyapısına, yüzey morfolojisine ve fotokatalitik performansına olan etkileri incelenmiştir.  TiO2 kaplamaların kristalin fazları X ışını kırınım cihazı (XRD) ile belirlenmiştir.  Yüzeylerin mikroyapısı, taramalı elektron mikroskobu (SEM) ile analiz edilmiştir.  Örneklerin fotokatalitik aktivite testleri, farklı zaman aralıklarında UV ışık altında metilen mavisi çözeltisinin bozundurma çalışmaları ile saptanmıştır.  En yüksek fotokatalitik aktivite 1 M elektrolit konsantrasyonunda üretilen TiO2 kaplamasında elde edilmiştir.  Deneysel çalışma sonuçları, hem morfolojideki hem de kristal yapıdaki değişikliklerin TiO2 kaplamaların fotoaktivitesi üzerinde güçlü bir etkiye sahip olduğunu göstermiştir. 

Keywords

• Titanyum dioksit,anodik spark oksitleme,yüzey morfolojisi,fotokatalitik,metilen mavisi

Characterization and photocatalytic properties of TiO2 coatings produced by anodic spark oxidation

Abstract

Photocatalytic degradation, one of the advanced oxidation technologies, has begun to be one of the promising methods for cleaning organic contaminants and for water treatment.  The most notable among photocatalysts is titanium dioxide (TiO2) semiconducting material with high photoactivity, stable and low cost.  In this study, TiO2 coatings were produced by anodic spark oxidation method on pure titanium in H3PO4 containing electrolyte.  The effects of different electrolyte concentrations (0.25-2 M H3PO4) on the microstructure, surface morphology and photocatalytic performance of TiO2 coatings have been investigated.  The crystalline phases of the TiO2 coatings obtained were determined by XRD.  The microstructure of the surfaces was analyzed by SEM.  The photocatalytic activity tests of the samples were evaluated by the degradation of aqueous methylene blue solutions under UV light at different time intervals.  The highest photocatalytic activity was obtained in the TiO2 coating produced in a 1 M electrolyte concentration.  The results indicated that changes in both the morphology and crystalline structure have a strong influence on the photoactivity of the TiO2 coatings. 

Keywords

• Titanium dioxide,anodic sparc oxidation,surface morphology,photocatalytic,methylene blue

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