Visible-light-responsive S-doped g-C3N4/α-Fe2O3 composite for dual degradation of bisphenol A and LDPE

Abstract

In this study, a sulfur-doped g-C₃N₄/α-Fe₂O₃ (SCF) nanocomposite was synthesized via a hydrothermal method to establish an efficient Z-scheme heterojunction for photocatalytic degradation of bisphenol A (BPA) and low-density polyethylene (LDPE). Sulfur doping considerably improved the visible-light absorption of g-C₃N₄, while α-Fe₂O₃ provided high oxidation potential, forming a robust interfacial charge-transfer pathway. Radical scavenging studies demonstrated the primary role of superoxide (O₂˙⁻) and hydroxyl (˙OH) radicals, verifying the Z-scheme mechanism over a conventional type-II heterojunction. The SCF nanocomposite exhibited exceptional photocatalytic activity, achieving a 28% LDPE weight loss over 10 days with a carbonyl index of 1.43, further corroborated by SEM images showing surface cavities due to degradation. Additionally, the BPA degradation efficiency reached an impressive 93% within just 60 minutes, demonstrating the superior catalytic efficiency of the nanocomposite. The catalyst exhibited remarkable photostability and recyclability, highlighting its potential for long-term environmental applications. The SCF photocatalyst demonstrates extraordinary effectiveness in degrading persistent pollutants and gives essential insights into the systematic design of Z-scheme heterojunctions for advanced environmental remediation, paving the way for future developments in photocatalytic degradation technology.