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Enstitüler18
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Fen Bilimleri Enstitüsü18
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Nanoteknoloji ve İleri Malzemeler Anabilim Dalı18
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Meslek Yüksekokulları10
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Teknik Bilimler Meslek Yüksekokulu10
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Fakülteler2
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Arazi Yönetimi, Taşınmaz Değerleme ve Geliştirme Anabilim Dalı (Disiplinlerarası)2
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Bilgisayar Mühendisliği Anabilim Dalı2
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Biyoloji Anabilim Dalı2
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Biyoteknoloji Anabilim Dalı2
New phosphine-amino-alcohol tridentate ligands for ruthenium catalyzed asymmetric transfer hydrogenation of ketones
Altan, Orhan | Yılmaz, Mustafa Kemal
New phosphine-amino-alcohol tridentate ligands (3a-c) and six new ruthenium complexes (4a-c and 5a-c) were synthesized and characterized. Catalytic activities of the metal complexes were tested on aryl alkyl ketones. All of the substrates were converted to related sec-alcohols in excellent yields (up to 99%), but enantioselectivities were insufficient (up to 40% ee). Despite the catalytic performance of 5a-c complexes can be considered as better than 4a-c, actually the catalytic activity of the complexes has been differed according to substrate. The ketones with less positive carbonyl carbons tend to give S-configuration with 5a-c and R-configuration with 4a-c. The catalytic performance of the complexes was rationalized by means of DFT calculations.
Nanostructured Photocatalysts Chapter 15 - Black phosphorus-based photocatalysts for energy and environmental applications
Altan, Orhan
Photocatalysis using semiconductor materials to conduct chemical reactions more efficiently with the aid of sunlight irradiation is foreseen as a promising solution to combat the energy and environmental pollution crisis that the world is facing at present. Finding a suitable semiconductor material that harvests a large portion of the sunlight spectrum with high photocatalytic efficiency lies in the heart of photocatalysis. In this regard, black phosphorus (BP), a rising star two-dimensional (2D) semiconducting material, has recently been regarded as an abundant, nontoxic, metal-free, and cheap photocatalyst with a suitable bandgap and broad light absorption ability. In this chapter, after the introduction of the general properties and synthesis of BP, the photocatalytic efficiency of BP a...
Boosting formic acid dehydrogenation via the design of a Z-scheme heterojunction photocatalyst: The case of graphitic carbon nitride/Ag/Ag3PO4-AgPd quaternary nanocomposites
Altan, Orhan
The development of an efficient, eco-friendly, practical, and selective way to decompose formic acid (FA) into H2 and CO2 is crucial for the utilization of FA as a chemical hydrogen storage material in hydrogen economy. In this regard, photocatalytic FA dehydrogenation attracts great attention owing to its potential to meet the above-mentioned requirements. Interestingly, there is no example of heterojunction photocatalyst that tunes the hole potential of the semiconductor, resulted in a better photocatalytic activity. We report herein for the first time the design and fabrication of a novel Z-scheme heterojunction photocatalyst for FA dehydrogenation, denoted as g-CN/Ag/Ag3PO4-AgPd comprising graphitic carbon nitride (g-CN) and Ag3PO4 semiconductors, Ag and AgPd alloy nanoparticles (NPs)....
The influence of band bending phenomenon on photocatalytic Suzuki-Miyaura coupling reaction: The case of AgPd alloy nanoparticles supported on graphitic carbon nitride
Altan, Orhan
The development of solar-powered systems for applications other than energy, such as photocatalytic organic reactions, will benefit in the resolution of environmental issues while also lowering production costs. In this study, the photocatalytic activity of g-CN(G)-AgPd, which was prepared by synthesizing AgPd alloy nanoparticles (NPs) on g-CN, was investigated in the Suzuki-Miyaura coupling (SMC) reaction. The photocatalytic activity of g-CN(G)-AgPd in an ethanol/water mixture at ambient temperature was discovered to be among the highest ever recorded. Under vis-light illumination, g-CN(G)-AgPd converted all of the aryl iodides and most of the aryl bromides investigated to desired coupling products in 15 min with excellent isolated yields, and it was used at least five times without signi...
A rare example of the in situ formation of palladium nanoparticles: The emergence of catalytically active palladium nanoparticles from Pd (II) phosphine complexes in the Suzuki–Miyaura coupling reaction
Altan, Orhan
Suzuki–Miyaura coupling (SMC) reactions are one of the most promising routes for carbon–carbon bond formation. It is believed that metal complexes, particularly palladium complexes, are the most effective catalysts for this purpose. However, the catalysis nature whether it is homogenous or heterogeneous is under debate. It is commonly believed that a homogenous catalysis pathway is responsible for the catalytic activity when the phosphine ligands are present in the structure due to the strong phosphorus-metal interactions. In this study, Pd (II) complexes of phosphino-benzaldoxime ligands were synthesized, characterized, and tested in SMC reactions. Interestingly, it was found that the catalytic activity increased by 11 times when the amount of catalyst was reduced by 10-fold and increased...
The rational design of a graphitic carbon nitride-based dual S-scheme heterojunction with energy storage ability as a day/night photocatalyst for formic acid dehydrogenation
Altan, Orhan
Photocatalytic formic acid dehydrogenation (FAD) has been regarded as one of the most promising methods of producing H2 in a sustainable manner. In the photocatalytic FAD reaction, photogenerated holes play an important role in the reaction mechanism and thus in the efficiency of photocatalysts. However, the design of photocatalytic systems capable of generating high hole potential without compromising the reducing ability of the photocatalyst is extremely rare for the FAD reaction. In this respect, we report herein a novel and highly efficient heterojunction photocatalyst composed of 2D graphitic carbon nitride, 2D MnO2, 1D MnOOH, and 0D PdAg alloy nanoparticles, denoted as GCN/MnO2/MnOOH-PdAg, that can create high reduction and oxidation potentials via a dual S-scheme heterojunction. The...
Seryum ilavesinin Mg-6Al-0.3Mn-1Sn alaşımının mekanik özelliklere etkisi
Ördek, Rezzan.
ÖZET SERYUM İLAVESİNİN Mg-6Al-0.3Mn-1Sn ALAŞIMININ MEKANİK ÖZELLİKLERE ETKİSİ Magnezyum alaşımlarının mukavemet/ağırlık, mukavemet/yoğunluk oranları diğer metal alaşımlarına göre dikkat çekici hale gelmiştir ve birçok çalışmaya konu olmuştur.Bu çalışmada, Mg-6Al-0,3Mn-1Sn (magnezyum-alüminyum-kalay) alaşımına farklı ağırlık oranlarında seryum (%0,5, 1 ve 2) kontrollü atmosferde soğuk kamaralı basınçlı döküm yöntemi ile üretilmiştir.Seryum ilavesinin Mg-6Al-1Sn alaşımının mekanik özelliklere etkisi incelenmiştir. Mikro yapı incelenmesi sertlik ve çekme dayanımı ayrıntılı olarak incelenmiş ve sonuçlar irdelenmiştir. Anahtar Kelimeler: Magnezyum Alaşımları, Magnezyum-Alüminyum Alaşımları, Seryum, Soğuk Kamaralı Basınçlı Döküm Yöntemi ABSTRACT EFFECT OF CERIUM ADDITION ON MECHANICAL PROPERTIES...
Solution-Processable Growth and Characterization of Dandelion-like ZnO:B Microflower Structures
Yıldırımcan, Saadet | Erat, Selma | Çetinkaya, Samed
Intrinsic and dandelion-like microflower nano-rod structures of boron-doped ZnO thin films were synthesized with an ecofriendly and cost-effective chemical bath deposition technique from an aqueous solution of zinc nitrate hexahdyrate [Zn(NO3)2.6H2O] as a precursor solution and boric acid as a doping solution. The boron concentrations were 0.1, 0.3, 0.5, 1.0, 3.0, 5.0, and 7.0 by volume. Scanning electron micrographs showed that doping with boron appears to hinder the vertical alignment of crystallites. Additionally, independent hexagonal nano-rod structures were observed to coalesce together to form dandelion-like structures on the film’s surface. The atomic ratio of the elements was determined via the X-ray photoemission spectrum technique. There were no substantial changes in th...
Synthesis and characterization of bis(diphenylphosphinomethyl)amino ligands and their Ni(II), Pd(II) complexes: Application to hydrogenation of styrene
Altan, Orhan
Transition metal complexes of Ni(II) and Pd(II) with ditertiary bis(diphenylphosphinomethyl)amino ligands, (Ph2PCH2)2NC(CH3)3 (1) and [(Ph2PCH2)Nm-PhSO3]Na (2) (Ph = phenyl), have been synthesized in good yields under nitrogen atmosphere by Schlenk technique. All complexes have been characterized using elemental analyses and spectroscopic techniques such as atomic absorption, FT-IR, and NMR (1H, 31P). Atomic absorption spectroscopic analysis showed that the reactions of ligands 1 and 2 with NiCl2 ⋅ 6H2O and [PdCl2(COD)] occurred in 1:1 molar ratio. The metal complexes [NiCl2(Ph2PCH2)2Nm-PhSO3Na] (4) and [PdCl2(Ph2PCH2)2Nm-PhSO3Na] (6) were found to be soluble in ethanolic and aqueous solutions, as well as slightly soluble in water. Electrochemical behaviors of complexes were investigated b...
EKOLOJİK SU ÜRÜNLERİ ÜRETİMİ
Bilgüven, Murat
Yirminci yüzyılın ikinci yarısında yaşanan hızlı sanayileşme ve nüfus artışı, çevre sorunları yanında, artan nüfusun yeterince beslenememesi yani açlık sorunun ortaya çıkmasına neden olmuştur. Artan nüfusun beslenme gereksinimi, insanoğlunu tarımda birim alandan; maksimum ürün almaya yöneltmiştir. Birim alandan yüksek verim almaya yönelik yoğun ve bilinçsiz tarım ilacı ve gübre kullanılması ve sonuç olarak, bu kimyasalların tarımsal ürünlerde oluşturduğu ve yeraltı sularına karışarak içme sularında yarattığı kalıntılar, insan sağlığını ve yaşamını tehdit etmeye başlamıştır. Verim artışı ile yetinilmemiş, genetik bilimin tüm teknolojileri de kullanılmaya başlanmış, bitki ve hayvanların DNA yapıları değiştirilmiş, melezleme ve klonlama yöntemleri uygulanmıştır. Tüm bunların sonucunda ekoloji...
Enhancement of photocatalytic activity of carbon nitride/black phosphorus/tungsten disulfide (CN/BP/WS2) heterojunctions via nickel doping in the hydrogen evolution reaction
Altan, Orhan
The complementary properties of mesoporous graphitic carbon nitride (m-CN) and black phosphorus (BP) as non-metallic semiconductors offer many opportunities for the rational design of efficient photocatalysts for the photocatalytic hydrogen evolution reaction (HER). However, pristine m-CN and BP exhibit significant photoinduced charge carrier recombination rates and weak light absorption, resulting in a low photocatalytic HER activity. To overcome these problems and improve their photocatalytic HER activities, rational design of heterojunctions is one of the most efficient ways. Here, we present for the first time the ternary m-CN/BP/WS2 dual S-scheme heterojunctions, prepared by combining as-prepared m-CN/BP hybrids with tungsten disulfide (WS2). Encouragingly, the ternary m-CN/BP/WS2 het...
N,N-Dialkil-n (4-bromo-benzoil) tiyoüre ligadlarının oksorenyum metal komplekslerinin sentezi ve karakterizasyonu
Selçik, Ali Nail.
ÖZET N,N-DİALKİL-N'-(4-BROMO-BENZOİL)TİYOÜRE LİGANDLARININ OKSORENYUM METAL KOMPLEKSLERİNİN SENTEZİ VE KARAKTERİZASYONU Bu tezde, N,N-dietil-N'-4-bromobenzoiltiyoüre (HL1), N,N-di-n-propil-N'-4- bromobenzoil-tiyoüre (HL2) ve N,N-di-n-butil-N'-4-bromobenzoiltiyoüre (HL3) ligandları sentezlendive yapıları elementel analiz, 1H NMR, 13C NMR ve FT-IR spektroskopileri ile karakterize edilmiştir. Elde edilen ligantların mononükleer ve dinükleer oksorenyum kompleksleri sentezlenmiştir. Bu komplekslerin moleküler yapıları çeşitli spektroskopik çalışmalar ile doğrulanmıştır. Ayrıca tek kristal kalitesine sahip oksorenyum komplekslerinin moleküler yapısı, tek kristal X-ışını kırınımı tekniği ile belirlenmiştir. Buna ek olarak, şelatlayıcı tiyoüre ligandlarının kullanılan çözücülere ve uygulanan reaks...
Gadolinyum katkılı ZrO2 katı elektrolitlerin üretilmesi, karakterizasyonu ve yakıt pili uygulaması
Yalaz, Emine.
ÖZET GADOLİNYUM KATKILI ZrO2 KATI ELEKTROLİTLERİN ÜRETİLMESİ, KARAKTERİZASYONU ve YAKIT PİLİ UYGULAMASI Bu çalışmada, Gd2O3-ZrO2 ikili sisteminin farklı mol oranlarında katkılanmasıyla üretilen katı oksit yakıt pilleri karakterize edilmiştir. Pechini yöntemiyle Gd2O3’ün ZrO2 içerisine katkılamaları yapılarak tetragonal fazın oluştuğu reaksiyon sıcaklıkları, süreleri ve stokiyometrik katkı aralıkları belirlenmiştir. Şerit döküm tekniğiyle imal edilen katı oksit yakıt pillerinin ince filmleri üretilmiştir. Üretilen bileşenler, XRD, SEM, DTA/TG ve empedans ölçüm yöntemleri ile karakterize edilmiştir. Şerit döküm tekniğiyle imal edilen katı elektrolit sistemlerinin empedans ölçümleri sonucunda en yüksek iletkenlik düzeyi, % 8 mol Gd2O3 katkılanmış katı elektrolit sistemi için 800 °C’de 4,74x10...
Farklı alttabanlar üzerinde CdSe yarıiletken ince filmlerin elde edilmesi
Septekin Görmüş, Fethiye.
ÖZET FARKLI ALTTABANLAR ÜZERİNE CdSe YARIİLETKEN İNCE FİLMLERİN ELDE EDİLMESİ Fethiye SEPTEKİN GÖRMÜŞ Kadmiyum Selenür (CdSe) nanotel ince filmleri 70 °C’de Kimyasal Depolama Yöntemi kullanılarak cam ve FTO alttabanlar üzerine depolanmıştır. CdSe/Cam ve CdSe/FTO nanotel filmleri hava atmosferinde 100 °C, 200 °C, 300 °C, 400 °C ve 500 °C’de 1 saat tavlandılar. Farklı sıcaklıklarda hava atmosferinde tavlanan ve tavlanmayan CdSe nanotel filmlerin optiksel, yapısal ve elektriksel özellikleri sırasıyla X‐ışını kırınımı (XRD), taramalı elektron mikroskobu (SEM), X‐ ışını enerji dağınımı (EDX), 4’lü prop ve Hall ölçüm metodu kullanılarak incelendiler. Optiksel yöntem filmlerin enerji aralığını (Eg) tanımlamada kullanıldı. Tavlama sıcaklığının artması ile fil...
A Faunistic Study on Papilionoidea and Hesperioidea (Lepidoptera) of Murat Mountain in Banaz, UŞAK Province, Turkey
Hüseyinoğlu, Yusuf
This study was carried out in Murat Mountain located in Banaz district (Uşak, Western Turkey), during 2000-2009 in order to collect data on Papilionoidea and Hesperioidea species, their distribution and current status. Butterflies (756) were caught with sweep nets from 28 localities during the field work of which 113 species and subspecies belonging to 7 families and 2 superfamilies were identified; 87 species were identified for the first time for Lepidoptera fauna of Uşak province and 103 species were identified for the first time for Murat Mountain (Banaz) fauna.
Boya temelli güneş pillerine yönelik ftalosiyanin türevlerinin sentezi ve performans çalışmalarının yapılması
Ercengiz, Narin Fulya.
ÖZET BOYA TEMELLİ GÜNEŞ PİLLERİNE YÖNELİK FTALOSİYANİN TÜREVLERİNİN SENTEZİ VE PERFORMANS ÇALIŞMALARININ YAPILMASI İnorganik fotovoltaik cihazlar ile karşılaştırıldığında düşük maliyet ve kolay işlemeden dolayı nanokristal yarı iletkenlere bağlı olan boya temelli güneş hücreleri üzerine yoğun çalışmalar yapılmıştır. Ftalosiyaninler 18 π elektrona sahip 8 karbon ve 8 azot atomuna bağlı 16 üyeli düzlemsel ve aromatik bileşiklerdir. Düzlemsel yapının azot atomları ile çevrili olmalarından dolayı da yüksek termal kararlılığa sahiptirler. Ayrıca ftalosiyaninler güçlü termal ve kimyasal kararlılıklarından ve zengin redoks özelliklerinden dolayı ideal ışık toplayıcı (lightharvester) moleküller olup, organik güneş hücrelerinden, tepkime katalizlemeye, nükleer kimyaya, optik veri depolamaya, foto d...