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

A high-performance g-C₃N₄/α-Fe₂O₃/Ppy photocatalyst for broad-spectrum degradation of waterborne dyes and pharmaceuticals under visible light

Ankoor Sura, Arjun Singh, Vandana Sehrawat, Sudha Narwal, Bharti Dahiya, Amanvir Singh, and Sonia Nain

Department of Chemistry, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, India

E-mail: sonianain.chem@dcrustm.org

Received: 20 December 2025  Accepted: 11 March 2026

Abstract:

Engineering photo redox interfaces that retain strong oxidative and reductive potentials while suppressing carrier recombination remains a defining challenge in photocatalysis. We report a ternary heterostructure integrating g-C₃N₄, α-Fe₂O₃, and polypyrrole (Ppy) into a direct Z-scheme nanocomposite (GFP2) that resolves this issue, by aligning the conduction and valence band edges through interfacial tuning, GFP2 enables directional charge separation, preserving photogenerated electrons on g-C₃N₄ for O₂ reduction and holes on Ppy for OH⁻ oxidation. This design delivers efficient photocatalytic degradation of both Rose Bengal (RB) and sulfamethoxazole (SMZ), reaching removal efficiencies of 91% and 88%, respectively, under visible light. Mechanistic validation through valence band XPS and scavenger quenching reveals superoxide radical (O₂^•⁻) and hydroxyl radical (OH^•) as the primary oxidative species, confirming Z-scheme mediated ROS generation. Interestingly, photocatalytic activity exhibits a non linear dependence on Ppy loading, peaking at intermediate composition (GFP2) where electronic continuity and optical accessibility are optimally balanced. By leveraging a three component, Z-scheme coupled interface with tunable energy landscapes and robust interfacial transport, this platform opens new avenues for light driven pollutant remediation in complex aqueous systems.

Graphical abstract

Keywords: Polypyrrole; g-C3N4; Fe2O3; Photocatalysis; Sulfamethoxazole; Rose Bengal; Z-cheme Heterojunction

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04807-4

Chemical Papers 80 (6) 6933–6945 (2026)