ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Na and P binary-doped g-C₃N₄/CoFe₂O₄ composites for photocatalytic degradation of Rhodamine B and Direct Orange 46 dye chemicals

Kübra Zenkin, Gizem Başaran Dindaş, Deniz Emre, Sefa Durmuş, Hüseyin Cengiz Yatmaz, and Ali Bilici

Department of Chemistry, Faculty of Arts and Sciences, Düzce University, Düzce, Türkiye

E-mail: yatmaz@gtu.edu.tr

Received: 15 November 2025  Accepted: 6 March 2026

Abstract:

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, pH_PZC, 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.

Keywords: Rhodamine B; Direct Orange 46; Composite photocatalyst; Carbon nitride; Dye chemicals; Environmental catalysis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04786-6

Chemical Papers 80 (6) 6559–6578 (2026)