Sol-jel Yöntemi ile Sentezlenen Bor ve/veya Azot Katkılı TiO2 Toz ve İnce Filmlerin Görünür ve Mor Ötesi Işık Altında Fotokatalitik Aktivitelerinin İncelenmesi

Yıl 2017, Cilt: 17 Sayı: 1, 227 - 238, 24.04.2017

Ali Erçin Ersundu

Öz

Bu çalışmada, farklı oranlarda B, N, B/N katkılı ve katkısız TiO2 fotokatalistleri sol-jel yöntemi ile toz ve ince film formunda üretilmiştir. İnce filmler daldırmalı kaplama yöntemi ile kaplamasız ve SiO2 ara katman kaplamalı soda kireç cam altlıklar üzerine kaplanmıştır. SiO2 ara katman kaplamalar, TiO2’nin ısıl işlemi sırasında altlık malzeme olarak kullanılan soda-kireç camındaki alkali iyonların film içine difüze ederek TiO2’nin faz dönüşümünü engellemesini ve fotokatalitik aktivitesini düşürmesini önlemek amacıyla uygulanmıştır. Katkılı ve katkısız TiO2 esaslı çözeltilerden elde edilen jellerin ısıl karakterizasyonları termogravimetrik diferansiyel termal analiz (TG/DTA) yöntemi ile gerçekleştirilmiştir. Elde edilen TG/DTA sonuçları ışığında, TiO2’nin fotokatalitik aktivitesi en yüksek olan anataz fazının kristalizasyon sıcaklığı belirlenmiştir. Anataz fazının kristalizasyon sıcaklığı ve cam altlık malzemenin cam geçiş sıcaklığı göz önünde bulundurularak, fotokatalistler hava ortamında 500 °C’de 1 saat ısıl işleme tabi tutulmuş ve fırın içerisinde oda sıcaklığına soğutulmuştur. Toz haldeki fotokatalistlerin faz karakterizasyonları X-ışınları difraksiyonu (XRD) tekniği ile, ince filmlerin optik karakterizasyonları ise UV-Vis spektrofotometre yöntemi ile gerçekleştirilmiştir. TiO2 yapısında katkı olarak B ve N’nin ayrı ayrı ve eşzamanlı bulunmasının mor ötesi ve görünür ışık fotokatalitik aktivitesine etkisi, organik bir kirlilik olan metilen mavisinin bozunması ile tespit edilmiştir. Metilen mavisinin bozunmasıyla fotokatalitik aktivite kinetik açıdan incelenmiş ve fotokatalistlerin fotokatalitik aktivite hız sabitleri hesaplanmıştır.

Anahtar Kelimeler

TiO2, Sol-jel, İnce film, Fotokatalitik aktivite

Kaynakça

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