Modulator-assisted solvothermal synthesis of CeO2 derived from Ce-BDC MOFs: effect on oxygen evolution reaction performance
Gözmen, Belgin | Görmez, Özkan | Çirmi, Doğan
In this study, the morphological, structural, and electrocatalytic properties of Ce-BDC-based metal–organic framework (MOF) materials synthesized under various conditions were comprehensively investigated. Four types of structures Ce-BDC, Ce-BDC-P, Ce-BDC*, and Ce-BDC*-P were prepared using a solvothermal method. The synthesis was carried out both under ambient and pressurized (P) conditions, and with or without acetic acid used as a modulator (*). To optimize the synthesis parameters, the amount of acetic acid (12.5, 25, and 50 Meq) was systematically varied, and among the samples, Ce-BDC*-50-P (synthesized under pressurized conditions with 50 Meq of acetic acid) was identified as exhibiting the highest electrocatalytic performance. Structural characterization was carried out using XRD, F...
Heterogeneous electro-fenton treatment of clofibric acid with a Fe3O4 loaded bifunctional carbon felt cathode via different anode types
Gözmen, Belgin | Çirmi, Doğan
Pharmaceutical pollutants such as clofibric acid pose significant risks to aquatic environments and human health. In this study, a bifunctional cathode (CF@Fe3O4) was synthesized by anchoring Fe3O4 nanoparticles onto carbon felt via a solvothermal method. The material was characterized using scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The CF@Fe3O4 cathode was then evaluated in a heterogeneous electro-Fenton system for clofibric acid degradation under varying pH and current conditions using platinum and boron doped diamond anodes. Using the CF@Fe3O4/Pt pair, the highest mineralization efficiency (82%) was achieved at pH 3 and 50 mA after 5 h, whereas higher current intensities resulted in decreased mineralization. In contrast, the CF@Fe3...
Carbon felt/CoFe2O4 cathode synthesis and use in the heterogeneous electro-Fenton process for vanillin oxidation
Gözmen, Belgin | Çirmi, Doğan
Synthetic vanillin is widely used in industries such as food and cosmetics, and it isalso produced as a by-product in various processes. This study was conductedto compare the degradation of vanillin using homogeneous and heterogeneouselectro-Fenton (EF) processes. Initially, electrocatalytic characterization was per-formed on a cathode material synthesized by solvothermal deposition of cobalt fer-rite (CoFe 2 O4 ) nanostructures onto a carbon felt (CF) substrate and compared withbare CF. Subsequently, the effectiveness of the CF@CoFe 2O 4 cathode material invanillin oxidation was compared at different pH values and currents with the hetero-geneous electro-Fenton process. The highest vanillin degradation and total organiccarbon (TOC) removal were achieved at pH 3. Following a 3 h heterogen...
Long-life (Co, Al, Mg)-doped LiMn1.5Ni0.5O4 cathodes prepared by co-precipitation method
Görmez, Özkan | Gözmen, Belgin | Çirmi, Doğan
The spinel cathode LiMn1.5Ni0.5O4 (LMN) is garnering significant interest in the realm of lithium-ion batteries owing to its economical nature, elevated operating voltage, high theoretical energy density, and commendable thermal stability at a charged state. Various doping elements have been suggested to enhance the discharge capacity and prolong the lifetime of the LMN cathode. In this study, three doping elements (cobalt, aluminum, and magnesium) are investigated and compared using different characterization techniques. All three elements proved to be effective in extending the cycle life. Among all three elements, cobalt exhibits the highest threshold for dopant concentration beyond which performance degradation initiates. The cathode material with the highest performance, LiMn1.5Ni0.4C...