Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Kahraman, ZeynepCOAR Access Rights: search.filters.coarAccessRights.metadata only access

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Phase-Dependent Optical, Photocatalytic and Capacitive Properties of Tungsten Oxide Nanowires
    (Royal Soc Chemistry, 2025) Kahraman, Zeynep; Gungor, Ahmet; Buldu-Akturk, Merve; Tan, Metin; Alp, Emre; Erdem, Emre; Genc, Aziz
    Transition metal oxides hold great promise across a wide range of applications due to favorable properties such as high abundance, low toxicity, and excellent stability. Nanoengineering approaches are essential for controlling the structural, optical, and electronic properties of these materials, enabling the achievement of desired characteristics in a cost-effective and environmentally friendly manner. In this study, we synthesize stoichiometric (WO3) and sub-stoichiometric (WO3-x) tungsten oxide nanowires by controlling their phases and morphologies through the hydrothermal method. This approach allows us to systematically investigate the effects of different phases and oxygen vacancies on the optical properties, as well as on photocatalytic and supercapacitance applications. We use the photodegradation of RhB as a benchmark for photocatalytic activity under various experimental conditions, revealing that oxygen vacancies significantly influence photocatalytic behavior. For example, WO3-x nanowires adsorb/degrade a substantial amount of RhB within short durations under ambient conditions, where WO3 nanowires are mostly inactive. The addition of H2O2 enhances the photocatalytic performance of WO3 nanowires over 30 minutes, with even better results under low pH conditions with H2O2. This study also explores the phase-dependent electrochemical properties of WO3 and WO3-x nanowires, providing insights into their potential for improved supercapacitor performance by leveraging their complementary properties in symmetric and asymmetric configurations. WO3-x, with a higher density of oxygen vacancies and thinner structure, offers enhanced conductivity and increased active sites for charge storage, resulting in superior specific capacitance and charge retention.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 4
    A Facile Method for Boosting the Graphitic Carbon Nitride's Photocatalytic Activity Based on 0d/2d S-Scheme Heterojunction Nanocomposite Architecture
    (Elsevier, 2024) Kahraman, Zeynep; Kartal, Uğur; Gent, Aziz; Alp, Emre
    Graphitic carbon nitride (g-C 3 N 4 ) has received significant interest as a metal -free photocatalyst. The S -scheme photocatalytic system has great potential to improve the charge separation in semiconductor photocatalysts. In this study, we have fabricated non-toxic and low-cost photocatalytic nanocomposites of 0D/2D S -scheme heterojunction composed of iron oxide and graphitic carbon nitride by a facile method. The developed facile method provides a sustainable way with a high atom economy to further enhance the photocatalytic performance of exfoliated g-C 3 N 4 . The 0D -iron oxide/2D-C 3 N 4 exhibited nearly 10 times better than bulk g-C 3 N 4 and almost 60 % better than exfoliated g-C 3 N 4 under simulated solar light irradiation. The experimental results demonstrated that the effective charge -carrier mechanism led to an improved generation of reactive oxygen species (ROSs), resulting in an impressive photocatalytic performance. A serial photocatalytic test was also conducted to understand photocatalytic reaction mechanisms with various scavengers.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Stable janus TaSe2 single-layers via surface functionalization
    (Elsevier Ltd., 2021) Kahraman, Zeynep; Başkurt, Mehmet; Yağmurcukardeş, Nesli; Chaves, A.; Şahin, Hasan
    First-principles calculations are performed in order to investigate the formation of Janus structures of single-layer TaSe2. The structural optimizations and phonon band dispersions reveal that the formation and stability of hydrogenated (HTaSe2), fluorinated (FTaSe2), and the one-side hydrogenated and one-side fluorinated (Janus-HTaSe2F) single-layers are feasible in terms of their phonon band dispersions. It is shown that bare metallic single-layer TaSe2 can be turned into a semiconductor as only one of its surface is functionalized while it remains as a metal via its two surfaces functionalization. In addition, the semiconducting nature of single-layers HTaSe2 and FTaSe2 and the metallic behavior of Janus TaSe2 are found to be robust under applied uniaxal strains. Further analysis on piezoelectric properties of the predicted single-layers reveal the enhanced in-plane and out-of-plane piezoelectricity via formed Janus-HTaSe2F. Our study indicates that single-layer TaSe2 is a suitable host material for surface functionalization via fluorination and hydrogenation which exhibit distinctive electronic and vibrational properties. © 2020 Elsevier B.V.