Browsing by Subject "Cyanide"
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Item Open Access A cyanide-based coordination polymer for hydrogen evolution electrocatalysis(Springer New York LLC, 2018) Alsaç, Elif Pınar; Ülker, E.; Nune, Satya Vijaya Kumar; Karadaş, FerdiAbstract: Research on H2 production has recently been directed to the development of cost-efficient and robust heterogeneous catalysts for hydrogen evolution reaction (HER). Given the promising catalytic activities of several cobalt-based systems and the robustness of Prussian blue analogues in harsh catalytic processes including water oxidation, a Co-Co Prussian blue analogue was investigated as a HER catalyst for the first time. Co-Co Prussian Blue modified fluorine doped tin oxide (FTO) electrode demonstrated a significant HER activity with an onset overpotential of 257 mV, a Tafel slope of 80 mV dec−1, and a turnover frequency of 0.090 s−1 at an overpotential of 250 mV. Comparative XPS, Infrared, and XRD studies performed on pristine and post-catalytic electrodes confirm the stability of the catalyst.Item Open Access Investigation of electrocatalytic performance of prussian blue analogues for water splitting(2017-09) Alsaç, Elif PınarResearch on H2 production has recently been directed to the development of cost-efficient and robust heterogeneous catalysts for splitting of water. While several Prussian blue analogues (PBAs) have been investigated as water oxidation catalysts, the field lacks a comprehensive study that focuses on the design of the ideal PBA for efficient water oxidation. Herein this thesis, a series of PBAs with different cyanide precursors were investigated to study the effect of hexacyanometal group to their electrocatalytic catalytic water oxidation activities. Cyclic voltammetry, chronoamperometry, and chronopotentiometry measurements reveal the close relation between the electron density of electroactive cobalt sites and electrocatalytic activity, which is also confirmed by Infrared and XPS studies. pH dependent cyclic voltammetry studies were also performed to gain insight about the catalytic mechanism and electronic structure of cyanide-based systems, to identify possible intermediates, and assign the rate-determining step of the process. In addition, a N-donor ligand, 1-heptyl 4-(4 pyridyl) pyridinium bromide, was used to prepare a new pentacyanoferrate complex. This complex was used to make a new series of PB analogues to investigate the effect of the change in the morphology to electrocatalytic water oxidation performance. Synthesis, characterization, and electrochemical experiments were performed to investigate electrocatalytic properties of PB analogues. With this synthesis route, the electroactive cobalt sites are increased approximately two-fold. It is observed that amorphous nature has positive impact on the catalytic activity when compared to cobalt hexacyanoferrates. A current density of 1 mA.cm-2 was achieved at an overpotential of 421 mV, which is much lower than those obtained with metal hexacyanometalates. Given the promising catalytic activities of several cobalt-based systems and the robustness of Prussian blue analogues in harsh catalytic processes including water oxidation, a Co-Co Prussian blue analogue was investigated as a Hydrogen evolution catalyst for the first time. Co-Co Prussian Blue modified FTO electrode demonstrated a significant Hydrogen evolution activity with an onset overpotential of 257 mV, a Tafel slope of 80.2 mV.dec-1, and a turnover frequency of 0.090 s-1 at an overpotential of 250 mV. Comparative XPS, Infrared, and XRD studies performed on pristine and post-catalytic electrodes confirm the stability of the catalyst.Item Open Access Investigation of the ideal composition of metal hexacyanocobaltates with high water oxidation catalytic activity(TÜBİTAK, 2019) Karadaş, FerdiThe electrocatalytic activities of Prussian blue analogues (PBAs) have recently received much attention due to their robustness and efficiency. Considering that PBAs with hexacyanocobaltate building block stand forward among other PBAs, a systematic study on a family of metal hexacyanocobaltates is presented in this study. Metal hexacyanocobaltates (M = Co, Mn, Ni, and Fe) were prepared, characterized, and electrochemical studies were performed. A series of mixed-metal cobalt-iron hexacyanocobaltates has also been studied to determine the ideal composition of a metal hexacyanocobaltate for electrocatalytic water oxidation process. The overall study clearly indicates that cobalt hexacyanocobaltate exhibits the highest electrocatalytic activity among all.Item Open Access Spill over effect of environmental consciousness: The Bergama environmental movement in Turkey(2001) Gezgör, BurcuThis thesis describes and analyses the Bergama environmental movement case in Tuikey that leceived a great attention in Turkish public opinion and interacted with vaiious actois. The Bergama case, which was triggered by the Eurogold company's gold mining opeiation using cyanide, illustrates the struggle of villagers in different forms of piotests and actions. In this study, we present an integrated approach by using two theoiies namely Resource Mobilization (RM) and New Social Movement (NSM) to piovide a comprehensive explanation of the social movement. This analysis indicates that inci easing awareness concerning a variety of issues such as environmental ones can cause people develop their capacity in dealing with problems and organizing actions. Consequently, they were enlightened to stand up for their rights, encouraged to participate in the decision- making process and introduced social and cultiu"al changes in their lives.Item Restricted Türkiye'de ilk büyük sivil itaatsizlik örneği: Bergama Hareketi(Bilkent University, 2020) Turan, Fatma Senem; Kılıç, Ömer Faruk; Erkaya, Nilsu; İpek, Mahmut Sefa; Çokuysal, Niyazi BerkayBu makale 90'lı yıllarda Türkiye'ye damga vurmuş, Türkiye'deki ilk büyük sivil itaatsizlik örneği olan Bergama Hareketini ele almaktadır. Bergama'nın Ovacık köyünde yapılacak olan siyanürlü altın madenciliğine karşı sergilenen toplumsal tutum, halkın çevre olaylarına gösterdiği tepkinin hukuksal boyut kazanması ve çıkan kararların 90'lı yılların siyasi atmosferini yansıtır nitelikte olması nedeniyle tarihi bir değer taşımaktadır. TBMM'de dahi yankı bulması ile yöre halkının tepkisi yöresel olmaktan çıkıp Türkiye'nin geneline yayılan bir mesele olmuş ve birçok kuruluş tarafından desteklenmiştir. Yaşadığı çevreyi korumak için başladıkları mücadele Türk hukuk dünyası açısından da örnek kararların ortaya çıkmasını sağlamış olması hususundan dolayı da Türk hukuk tarihi açısından önemli bir yere sahiptir