Mechanochemical Synthesis of GCN/Nb2O5/Bi2O3Ternary Composite Photocatalyst for Enhanced Visible Light Driven Degradation of Organic Pollutants

This study investigates the development of a graphitic carbon nitride/niobium pentoxide/bismuth oxide (GCN/Nb₂O₅/Bi₂O₃) ternary composite photocatalyst for enhanced methylene blue (MB) degradation under visible light irradiation. The g-C₃N₄ (GCN) was synthesized using a simple thermal method, and the ternary nanocomposite was prepared via a mechanochemical route. The GCN/Nb₂O₅/Bi₂O₃ ternary composite exhibited superior photocatalytic activity compared to pristine GCN and GCN-based binary composites, achieving 98% MB degradation within 105 min under visible light irradiation. The combined action of GCN, Nb₂O₅, and Bi₂O₃ synergistically enhances performance by effectively separating charges and minimizing the recombination of photogenerated electron-hole pairs. Scavenger experiments showed that holes (h⁺) and hydroxyl radicals (•OH) play the primary roles in MB degradation. The GCN/Nb₂O₅/Bi₂O₃ ternary composite demonstrated good stability, maintaining its photocatalytic activity over five consecutive reaction cycles. This work highlights the potential of GCN/Nb₂O₅/Bi₂O₃ ternary composite for efficient wastewater treatment applications.