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    Na and P binary-doped g-C3N4/CoFe2O4 composites for photocatalytic degradation of Rhodamine B and Direct Orange 46 dye chemicals
    (Springer Int Publ Ag, 2026) Zenkin, Kubra; Basaran Dindas, Gizem; Emre, Deniz; Durmus, Sefa; Yatmaz, Huseyin Cengiz; Bilici, Ali
    The design and synthesis of innovative photocatalyst systems are crucial for the removal of pollutants from wastewater. In this study, sodium and phosphorous co-doped g-C3N4@CoFe2O4 (NaPCN@CFO) composite photocatalysts with the four different composition ratios (containing 5, 10, 20, and 50% CFO contents as weight) were prepared and used as photocatalysts for the decolorization of Rhodamine B (Rh-B) and Direct Orange 46 (DO-46) organic dyes. NaPCN, CFO, and NaPCN@CFO composites were prepared by thermal polymerization, hydrothermal treatment, and simple ultrasonic mixing, respectively. UV-DRS, PL, FTIR, XRD, TEM, SEM, EDX, EDS mapping, XPS, BET, pHPZC, and zeta sizer measurements confirmed the successful formation of the composites. The effects of varying CFO contents on the nanocomposite structure and photocatalytic properties were investigated. The photocatalytic activity for Rh-B decolorization decreased as the CFO content in the composite catalyst increased, with the highest color removal efficiency (86%) achieved by NaPCN@CFO-5. In contrast, for DO-46, the removal efficiency was enhanced, reaching 92% for NaPCN@CFO-5 and NaPCN@CFO-10, but decreased for higher CFO loadings (75% for NaPCN@CFO-20 and 60% for NaPCN@CFO-50). These findings suggested that although increasing the CFO content did not significantly improve the decolorization of the cationic dye (Rh-B), it enhanced the efficiency of the anionic dye (DO-46), underscoring the importance of dye structure and catalyst composition in photocatalytic processes.
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    Salvia officinalis leaf extract-stabilized NiO NPs, ZnO NPs, and NiO@ZnO nanocomposite: Green hydrothermal synthesis, characterization and supercapacitor application
    (Springer Heidelberg, 2024) Zenkin, Kuebra; Durmus, Sefa; Emre, Deniz; Bilici, Ali; Yilmaz, Selehattin
    In this study, NiO nanoparticles (NiO NPs) and NiO@ZnO nanocomposite were synthesized for the first time using a Salvia officinalis (S. officinalis) extract-assisted hydrothermal process. The S. officinalis leaf extract served as a natural reducing and capping agent. The synthesized NiO NPs, ZnO NPs, and NiO@ZnO nanocomposite were thoroughly characterized using various techniques, including Fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), energy-dispersive spectrometry (EDS) mapping, vibrating sample magnetometer (VSM), and cyclic voltammetry (CV) analysis. The direct and indirect band gap energies of NiO NPs, ZnO NPs, and NiO@ZnO were found to be 3.00, 2.28, and 2.71 eV, and 2.63, 1.91, and 2.23 eV, respectively. The crystallite sizes were analyzed using PXRD spectra through Scherrer and Williamson-Hall (W-H) methods. TEM analysis revealed that the average particle sizes of NiO NPs, ZnO NPs, and NiO@ZnO were 16.0, 207.5, and 31.0 nm, respectively. The magnetic properties of all nanomaterials were assessed via the VSM technique. Specific capacitance (Cs) values, determined from CV voltammograms, were 196.8, 632.4, and 785 Fg-1 at a scan rate of 25 mVs-1 for NiO NPs, ZnO NPs, and NiO@ZnO, respectively. These findings suggest that the green-synthesized NiO@ZnO nanocomposite holds significant potential as a high-performance electrode material for supercapacitor applications.