Bi-doped g-C3N4/Bi2WO6 ternary composites for superior photocatalytic degradation of reactive orange 16 under visible light irradiation

Abstract

Because of unrestricted disposal, the concentration of reactive dyes in wastewater is gradually increasing. Owing to their eco-toxicity their removal becomes so crucial. In this regard, Bi(0)-doped g-C₃N₄/Bi₂WO₆ (g-C₃N₄/Bi@Bi₂WO₆) nanocomposites were prepared by wet impregnation followed by calcination. Remarkably, the Bi(0) doping occurs concertedly during the preparation of Bi₂WO₆ without the addition of any extra reducing agent. The efficacy of the photocatalyst for eliminating reactive orange 16 was evaluated under visible light irradiation. XRD, FESEM, HRTEM, DRS, XPS, BET, etc., were employed to characterize these hybrids. The presence of Bi(0) was confirmed by HRTEM and XPS. Increasing the g-C₃N₄ content enhances the specific surface and reduces the charge transfer resistance. Among the various photocatalysts, the 20 wt% g-C₃N₄/Bi@Bi₂WO₆ hybrid owned the highest degradation efficiency of 89 % after 300 min of reaction time. The controlled experiments confirm the participation of holes and superoxide anions during the reactions. The various reaction intermediates were detected by HRMS providing the necessary evidence about the mechanism. The heterostructure possesses excellent reusability and stability. Due to enhanced catalytic activity, high stability, and ease of synthesis, the reported composite can be considered as a promising catalyst for the degradation of pollutants.