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Öğe Amperometric Glucose Biosensor Based on Gold-Deposited Polyvinylferrocene Film on Pt Electrode(Elsevier Advanced Technology, 2006) Sulak, Meral Topçu; Gökdoğan, Özlem; Gülce, Ahmet; Gülce, HandanThe preparations and performances of the novel amperometric biosensors for glucose based on immobilized glucose oxidase (GOD) on modified Pt electrodes are described. Two types of modified electrodes for the enzyme immobilization were used in this study, polyvinyl ferrocene (PVF) coated Pt electrode and gold deposited PVF coated Pt electrode. A simple method forthe immobilization of GOD enzyme on the modified electrodes was described. The enzyme electrodes developed in this study were called as PVF-GOD enzyme electrode and PVF-Au-GOD enzyme electrode, respectively. The amperometric responses of the enzyme electrodes were measured at constant potential, which was due to the electrooxidation of enzymatically produced H2O2. The electrocatalytic effects of the polymer. PVF. and the cold particles towards the electrooxidation of the enzymatically generated H2O2 offers sensitive and selective monitoring of glucose. The biosensor based on PVF-Au-GOD electrode has 6.6 times larger maximum current, 3.8 times higher sensitivity and 1.6 times larger linear working portion than those of the biosensor based on PVF-GOD electrode. The effects of the applied potential. the thickness of the polymeric film. the amount of the immobilized enzyme, pH. the amount of the deposited An, temperature and substrate concentration on the responses of the biosensors were investigated. The optimum pH was found to be pH 7.4 at 25 degrees C. Finally the effects of interferents, stability of the biosensors and applicability to serum analysis of the biosensor were also investigated.Öğe Çinko oksit nanopartikülleri sentezi ve karakterizasyonu(Selçuk Üniversitesi Mühendislik Fakültesi, 2014) Özbay, Emre; Gülce, HandanBu çalışmada, çinko oksit nanopartikülleri Adibik Asit aile çinko asetat reaksiyonundan kimyasal çöktürme yöntemiyle ilk kez üretilmiştir. Çinko Asetat ve Adibik Asit reaksiyonu ile elde edilen malzeme farklı sıcaklıklarında kalsine edilerek kristal büyüklükleri 20-40 nm arasında değişen ZnO nanopartiküllerinin elde edilmiştir. Kalsinasyon sıcaklığının üretilen materyallerin yapılarına etkisini incelemek için XRD, SEM, FT-IR, yöntemleri kullanılmıştır. FT-IR spektrumları üretilen malzemenin ZnO olduğunu kanıtlamıştır. XRD sonuçlarından sentezlenen ZnO nanopartiküllerinin hegzagonal bir yapıya sahip olduğu ve kalsinasyon sıcaklığının artmasıyla kristal yapıda büyüme olduğu belirlenmiştir. SEM fotoğraflarını incelenmesi ile kalsinasyon sıcaklığının morfolojik yapıyı değiştirdiği görülmüştür.Öğe Preparation of polyaniline/ZnO nanocomposites by using arc-discharge synthesized zno nanoparticles and photocatalytic applications(Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2012) Eskizeybek, Volkan; Gülce, Handan; Gülce, Ahmet; Avcı, Ahmet; Akgül, EdaPolyaniline (PANI) and PANI/ZnO nanocomposites were synthesized by the chemical oxidative polymerization of aniline and aniline with the presence of ZnO nanoparticles, respectively. The ZnO nanoparticles synthesized by arc-discharge method were used in this study to produce PANI/ZnO nanocomposites. Aniline/ZnO nanoparticles molar ratio was changed to investigate the effect of ZnO nanoparticles to the characteristic of the PANI. The scanning electron microscope analysis showed that ZnO nanoparticles were completely dispersed in PANI matrix homogeneously. It is revealed that shifting to the higher wavenumbers occurred by the increasing ZnO nanoparticle content in fourier transform infrared spectroscopy analysis. Furthermore, degradation of malachite green in aqueous solution was carried out with the prepared nanocomposites under ultraviolet irradiation. The experimental results showed that 1.2 g/L of the nanocomposite could catalyze green solution above 98% after 180 min of irradiation.Öğe Preparation of the New Polyaniline/ZnO Nanocomposite and Its Photocatalytic Activity for Degradation of Methylene Blue and Malachite Green Dyes Under UV and Natural Sun Lights Irradiations(ELSEVIER, 2012) Eskizeybek, Volkan; Sarı, Fahriye; Gülce, Handan; Gülce, Ahmet; Avcı, AhmetA new polyaniline (PANI) homopolymer and PANI/ZnO nanocomposite have been successfully synthesized in aqueous diethylene glycol solution medium via the chemical oxidative polymerization of aniline. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, FTIR spectra, UV-vis spectroscopy measurements were used to characterize the resulting PANI homopolymer and PANI/ZnO nanocomposite photocatalysts. The photocatalytic activities of PANI homopolymer and PANI/ZnO nanocomposites were investigated by the degradation of methylene blue (MB) and malachite green (MG) dyes in aqueous medium under natural sunlight and UV light irradiation and the efficiency of the catalysts have been discussed in detail. Results indicate that the addition of the ZnO nanoparticles to the PANI homopolymer enhance the photocatalytic efficiency under natural sunlight irradiation and a little amount of PANI/ZnO nanocomposite photocatalyst (0.4 g/L) degrades both of the dye solutions (MB or MG) with 99% efficiency after 5 h of irradiation under natural sunlight.