Photocatalytic activity of CuBi₂O₄/CuO heterojunction for methylene blue degradation under visible light irradiation

We successfully synthesized CuBi₂O₄/CuO heterojunction with various mass ratios using a simple grinding-annealing method. The synthesized materials exhibited optical band gap values around 1.70 eV, suggesting their capability to absorb visible light. CuBi₂O₄/CuO was synthesized using mass ratios of 1:1, 1:2, and 2:1, which are referred to as CuBi₂O₄/CuO I, CuBi₂O₄/CuO II, and CuBi₂O₄/CuO III, respectively. The photocatalytic efficacy of CuBi₂O₄/CuO was evaluated for methylene blue degradation. Among the various mass ratios of CuBi₂O₄/CuO that were tested, CuBi₂O₄/CuO II exhibited the highest photocatalytic degradation efficiency (81.1 %) when subjected to visible light within 180 min. HR-TEM analysis validated the heterojunction formation of CuBi₂O₄/CuO between CuBi₂O₄ and CuO. Utilizing an adequate quantity of CuBi₂O₄ and CuO at a mass ratio 1:2, produces a synergistic effect in the heterojunction system of exceptional superiority. This work examines how the CuBi₂O₄/CuO mass ratio affects the breakdown of organic pollutants under visible light exposure.