Preparation of Bi2CrO6/CuO heterostructure nanocomposite to increase methylene blue decomposition under visible light irradiation

In this study, the Bi₂CrO₆/CuO nanocomposite was used for the photocatalytic degradation of methylene blue (MB) under visible light. Nanocomposites with different ratios (1:1, 1:2, 2:1) were synthesized under hydrothermal conditions and investigated for MB removal. Various characterization techniques, including XRD, FT-IR, FE-SEM, BET, DRS, PL, and EDS, were employed to elucidate the physicochemical aspects of the catalysts. The 2:1 nanocomposite ratio was selected as the photocatalyst with the highest removal efficiency (85 %). Four main factors, including initial concentration, solution pH, catalyst dose, and light intensity, were studied using the response surface methodology (RSM) and the Box-Behnken model. Under optimal conditions, the MB removal efficiency reached 90.06 %. Additionally, the effect of oxidizing agents (H₂O₂) on the enhanced removal of MB was investigated. The improved photocatalytic performance of the Bi₂CrO₆/CuO (2:1) nanocomposite is attributed to visible light absorption, the formation of a p-n heterostructure, efficient charge separation via the S-scheme mechanism, and increased charge carrier lifetime. Moreover, economic calculations showed that the estimated costs for the photocatalytic removal of MB from wastewater are cost-effective.