Hidrotermal yöntemle farklı morfolojilerde çinko-kalay oksit (Zn2SnO4) nanoyapıların sentezi ve fotokatalitik özelliklerinin incelenmesi
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Dosyalar
Tarih
2019
Yazarlar
Dergi Başlığı
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Cilt Başlığı
Yayıncı
Selçuk Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Üç bileşenli, yeni nesil n-tipi bir yarı iletken olan çinko-kalay oksit (Zn2SnO4, ZTO) nanoparçacıkların sentezi ve fotokatalitik (PC) aktivitesinin incelenmesi son zamanlarda dikkat çeken bir araştırma alanıdır. ZTO nanoparçacıklar yüksek elektron (e-) ve boşluk (h+) hareketliliği ve düşük şiddetteki ışığı emme kabiliyeti gibi sahip olduğu üstün optik özellikleri nedeniyle organik kirliliklerin giderilmesinde tercih edilen uygun bir fotokatalizör malzemedir. ZTO nano yapıların yapısal ve optik özellikleri çoğunlukla bu parçacıkların sentez şartlarına bağlıdır. Bu nedenle etkili PC aktiviteye sahip ZTO nano yapıların kontrollü ve tekrarlanabilir şekilde sentezlenmesi büyük önem taşımaktadır. Söz konusu üretim yöntemlerinin, sentezlenen ZTO nanoparçacıkların boyut ve şekil kontrolüne imkân vermesinin yanı sıra, karmaşık donanım ve alt yapı gerektirmeden uygulanabilir olması ekonomik açıdan verimli ve yüksek miktarda üretim sağlaması açısından önemlidir. Bu çalışmada ek bir ısıl işleme gerek duyulmadan düşük sıcaklık ve yüksek pH değerlerinde, istenilen saflıkta ve kristallikte ZTO nanoparçacıkların sentezine imkân sağlayan hidrotermal yöntem, sentez methodu olarak seçilmiştir. Bu tez çalışmasında genel olarak iki ana konuya odaklanılmıştır; (i) ZTO nanoparçacıkların hidrotermal yöntemle farklı çözücü ortamlarında sentezlenmesi ve (ii) sentezlenen nanoparçacıkların PC özelliklerinin belirlenmesi. TÜBİTAK 216M011 numaralı projenin desteğiyle gerçekleştirilen deneylerde ZTO nanoparçacıkların hidrotermal yöntemle sentezlenmesi esnasında ilk başta çözücü ortamı olarak deiyonize su (DI-su) kullanılmış ve bu ortamda sentez için gerekli olan çeşitli parametreler (sıcaklık, süre, pH, başlangıç kimyasalların oranı vb.) belirlenmiştir. Ardından belirlenen en uygun deneysel şartlarda farklı çözücü ortamları kullanılarak sentez prosedürü tekrarlanmıştır. Deneyler sırasıyla DI-su:Etanol, DI-su:Etilen Glikol, DI-su:Metanol ve DI-su:Propanol karışımlarının, çözücü ortamı olarak kullanılmasıyla gerçekleştirilmiştir. Çalışmanın ikinci kısmında ise farklı çözücü ortamlarında hidrotermal yöntemle sentezlenen ZTO nanoparçacıkların PC aktivitesinin belirlenmesi amacıyla Rodamin B (RhB) organik boyar maddesinin ultraviyole (UV) ve görünür ışık altında bozunum davranışı incelenmiştir. Nanoparçacıkların PC özelliklerinin geliştirilebilmesi için farklı katalizör miktarı, çözelti pH'ı, ışığa maruz kalma süresi ve ışıkla boya çözeltisi arasındaki mesafe gibi parametreler detaylı bir şekilde incelenmiştir. ZTO nanoparçacıklar ilave edilmeden önce UV ışık altında oldukça kararlı davranan RhB çözeltisine DI-su ortamında sentezlenen ZTO nanoparçacıkların ilave edilmesiyle boya çözeltisinin 120 dakika ışığa maruz bırakılması sonucunda RhB boyasının % 97,90'ının bozunduğu gözlemlenmiştir. DI-su:Etanol ortamında sentezlenen nanoparçacıkların yine UV ışık altındaki bozunum değeri 120 dakikada % 86,47'dir. Özetle çözücü ortamının değiştirilmesiyle PC aktivitenin iyileştirilebileceği bulunmuştur. Görünür ışık deneylerinde en iyi bozunum değerine DI-su ortamında sentezlenen ZTO nanoparçacıkların varlığında gerçekleştirilen deneylerde ulaşılmıştır (400 dakikada % 88,18). Sonuç olarak yapılan tez çalışması kapsamında ZTO nanoparçacıkların hidrotermal yöntemle sentezi ve UV/görünür ışık altında sergilediği PC aktivitesi detaylı bir şekilde incelenmiş ve en uygun sentez/PC deney şartları belirlenmiştir.
The synthesis of zinc-tin oxide (Zn2SnO4, ZTO) nanoparticles which are a new generation of three-component n-type semiconductors and investigation of their photocatalytic activity have attracted extensive research attention. ZTO nanoparticles are preferred photocatalyst materials for the removal of organic impurities due to their superior optical properties such as high electron and void mobility and low light absorbing ability. The structural and optical properties of the ZTO nanostructures often depend on the synthesis conditions of these particles. Therefore, controlled and reproducible synthesis of ZTO nano structures with effective photocatalytic activity is of great importance. The fact that these production methods allow the size and shape control of the synthesized ZTO nanoparticles as well as the fact that they can be applied without requiring complex equipment and infrastructure is another important issue in terms of providing economically efficient and high production. In this study, hydrothermal method was selected as the synthesis method which enables the synthesis of ZTO nanoparticles of desired purity and crystallinity at low temperature and high pH values without the need for additional heat treatment. This thesis focuses on two main topics; (i) Synthesis of ZTO nanoparticles by hydrothermal method in different solvent media; and (ii) determination of photocatalytic properties of the nanoparticles. In the experiments carried out with the support of TÜBİTAK 216M011 project, deionized water (DI-water) medium was used as the solvent during the synthesis of ZTO nanoparticles by hydrothermal method, and various parameters (temperature, duration, pH, starting chemicals ratio etc.) required for synthesis were determined. The synthesis procedure was then carried out using different solvent media under the most suitable experimental conditions. Experiments were carried out using DI-water: Ethanol, DI-water: Ethylene Glycol, DI-water: Methanol and DI-water: Propanol mixtures as the solvent medium, respectively. In the second part of the study, the degradation behavior of Rhodamine B (RhB) organic dyes under UV and visible light was investigated in order to determine the photocatalytic activity of ZTO nanoparticles synthesized by hydrothermal method in different solvent environments. In order to improve the photocatalytic properties of nanoparticles, degradation experiments were examined in detail such as different amount of catalysis, solution pH, light exposure time and distance between light and dye solution. Although RhB solution without ZTO nanoparticles behaved very stable under UV light, 97.90 % of the dye solution is degraded by adding ZTO nanoparticles under the 120 minutes light exposure. Furthermore, the decomposition value of RhB in the presence of nanoparticles synthesized in ethanol medium reached 86.47 % after 120 minutes UV light exposure. In summary, it has been found that photocatalytic activity can be improved by changing the solvent medium. In visible light experiments, the best degradation value was obtained in the experiments carried out in the presence of nanoparticles synthesized in DI-water medium (88.18 % in 400 minutes). As a result of this thesis, the synthesis of ZTO nanoparticles by hydrothermal method and photocatalytic activity of these nanoparticles under UV / visible lights were examined in detail and the most appropriate synthesis / photocatalytic test conditions were determined.
The synthesis of zinc-tin oxide (Zn2SnO4, ZTO) nanoparticles which are a new generation of three-component n-type semiconductors and investigation of their photocatalytic activity have attracted extensive research attention. ZTO nanoparticles are preferred photocatalyst materials for the removal of organic impurities due to their superior optical properties such as high electron and void mobility and low light absorbing ability. The structural and optical properties of the ZTO nanostructures often depend on the synthesis conditions of these particles. Therefore, controlled and reproducible synthesis of ZTO nano structures with effective photocatalytic activity is of great importance. The fact that these production methods allow the size and shape control of the synthesized ZTO nanoparticles as well as the fact that they can be applied without requiring complex equipment and infrastructure is another important issue in terms of providing economically efficient and high production. In this study, hydrothermal method was selected as the synthesis method which enables the synthesis of ZTO nanoparticles of desired purity and crystallinity at low temperature and high pH values without the need for additional heat treatment. This thesis focuses on two main topics; (i) Synthesis of ZTO nanoparticles by hydrothermal method in different solvent media; and (ii) determination of photocatalytic properties of the nanoparticles. In the experiments carried out with the support of TÜBİTAK 216M011 project, deionized water (DI-water) medium was used as the solvent during the synthesis of ZTO nanoparticles by hydrothermal method, and various parameters (temperature, duration, pH, starting chemicals ratio etc.) required for synthesis were determined. The synthesis procedure was then carried out using different solvent media under the most suitable experimental conditions. Experiments were carried out using DI-water: Ethanol, DI-water: Ethylene Glycol, DI-water: Methanol and DI-water: Propanol mixtures as the solvent medium, respectively. In the second part of the study, the degradation behavior of Rhodamine B (RhB) organic dyes under UV and visible light was investigated in order to determine the photocatalytic activity of ZTO nanoparticles synthesized by hydrothermal method in different solvent environments. In order to improve the photocatalytic properties of nanoparticles, degradation experiments were examined in detail such as different amount of catalysis, solution pH, light exposure time and distance between light and dye solution. Although RhB solution without ZTO nanoparticles behaved very stable under UV light, 97.90 % of the dye solution is degraded by adding ZTO nanoparticles under the 120 minutes light exposure. Furthermore, the decomposition value of RhB in the presence of nanoparticles synthesized in ethanol medium reached 86.47 % after 120 minutes UV light exposure. In summary, it has been found that photocatalytic activity can be improved by changing the solvent medium. In visible light experiments, the best degradation value was obtained in the experiments carried out in the presence of nanoparticles synthesized in DI-water medium (88.18 % in 400 minutes). As a result of this thesis, the synthesis of ZTO nanoparticles by hydrothermal method and photocatalytic activity of these nanoparticles under UV / visible lights were examined in detail and the most appropriate synthesis / photocatalytic test conditions were determined.
Açıklama
Anahtar Kelimeler
Çinko-kalay oksit, Fotokatalitik aktivite, Hidrotermal yöntem, Zinc-tin oxide, Photocatalytic activity, Hydrothermal method
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Keleş, Z. (2019). Hidrotermal Yöntemle Farklı Morfolojilerde Çinko-Kalay Oksit (Zn2SnO4) Nanoyapıların Sentezi ve Fotokatalitik Özelliklerinin İncelenmesi. ( Yüksek Lisans Tezi). Selçuk Üniversitesi, Fen Bilimleri Enstitüsü, Konya.
