Browsing by Author "Tuna, Ozlem"

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Incorporation of CuWO4 With Hollow Tubular g-C3N4: Harnessing the Potential in Photocatalytic Degradation, Hydrogen Production, and Supercapacitor Applications
(Elsevier Ltd, 2026) Erdem, Nurseli Görener; Ca̧ǧlar, Başar; İnan, Ece; Tuna, Ozlem; Firtina Ertis, Irem; Bilgin Simsek, Esra; 01. Izmir Institute of Technology
Driven by the urgent need for sustainable energy conversion and environmental remediation technologies, the development of multifunctional materials has gained growing interest. Herein, a bifunctional heterostructure was fabricated by depositing copper tungstate (CuWO4) spherical particles over hollow tubular graphitic carbon nitride (HTCN) using an ultrasonic-assisted thermal impregnation method. The photocatalytic activities were evaluated through tetracycline degradation and hydrogen evolution tests, while electrochemical measurements were conducted to assess the supercapacitor performance. CuWO4@HTCN composite achieved up to 83% degradation efficiency, a hydrogen evolution rate of 2538 μmol g1 h−1, and a specific capacitance of 212 F g1, demonstrating its strong potential as a multifunctional material for solar-driven environmental and energy storage applications. The enhanced photocatalytic performance was attributed to extended visible light absorption ability, efficient charge separation, and suppressed electron–hole recombination resulting from the formation of a Z-scheme heterojunction. Furthermore, the superior capacitance behavior was ascribed to enhanced electrical conductivity and ion transport, enabled by the porous, nitrogen-rich HTCN structure. The increased HTCN content in the composite improved pore accessibility and active site availability while an excessive amount of CuWO4 reduced electrochemical performance. These results highlight the multifunctional applicability of CuWO4@HTCN composite in photocatalytic hydrogen production and supercapacitor systems, emphasizing their relevance for renewable energy technologies. © 2025 Elsevier B.V., All rights reserved.
Citation - Scopus: 1
Unveiling the Bi-Functional Potential of Cowo4 Hybridized With Tubular G-C3n4 for Highly Photocatalytic Hydrogen Production, Water Purification and Supercapacitance Activities
(Pergamon-elsevier Science Ltd, 2025) Erdem, Nurseli Gorener; Tuna, Ozlem; Inan, Ece; Caglar, Basar; Ertis, Irem Firtina; Simsek, Esra Bilgin; 03.06. Department of Energy Systems Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
In this paper, CoWO4 nanospheres were successfully hybridized with graphitic carbon nitride with tubular morphology (TCN) and the photocatalytic antibiotic degradation, hydrogen evolution and supercapacitor performances were examined in detail. The morphological, structural and optical properties were characterized. The hybrid CoWO4/TCN-2 catalyst showed the highest tetracycline degradation efficiency with the rate constant of 0.0198 min(-1) which was 3.73 and 5.21 times greater than that of CoWO4 and TCN samples, respectively. The rate of photocatalytic hydrogen evolution was found to be 1997 mu mol/g.h for CoWO4/TCN-2 which was 2.03-fold and 1.09-fold higher than of TCN and CoWO4 samples, respectively. Electrochemical analysis revealed that the charge storage in CoWO4, TCN, and CoWO4/TCN electrodes was mainly governed by faradaic processes. All electrodes showed high-rate capability (>85 %), coulombic efficiency (>90 %) and cycle stability (>100 %). While CoWO4 and TCN electrodes show higher redox activities and specific capacitances than CoWO4/TCN composites, this limitation is mitigated by enhanced wettability in CoWO4/TCN electrodes. Notably, the CoWO4/TCN-2 electrode exhibits superior long-term capacitance, surpassing the TCN electrode after 2000 GCD cycles. This work offers new application areas for the metal tungstate/carbon nitride photocatalysts with improved photocatalytic and electrochemical performances.