Cu 2 O / ZnO /Polyaniline Ternary Composite for Enhanced Visible‐Light Photocatalytic Degradation of Methylene Blue

Copper(I) oxide (Cu 2 O) is a p‐type semiconductor with promising potential for photocatalytic applications; however, its practical application is limited by photo corrosion, which can reduce photocatalytic performance and stability. So, a ternary Cu 2 O/ZnO/polyaniline (PANI) composite was synthesized using a combination of sol‐mixing and in situ polymerization at room temperature to improve the photocatalytic performance in dyes photodegradation. In this work, Cu 2 O, Cu 2 O/ZnO, and Cu 2 O/ZnO/PANI composites with different aniline volumes (0.03, 0.05, and 0.10 mL) were prepared and characterized using FTIR, XRD, SEM‐EDS, PL spectroscopy, and UV–Vis DRS. The characterization results confirmed the characteristic functional groups and crystalline phases of the constituent materials. The incorporation of ZnO and PANI also modified the optical properties of Cu 2 O. The photocatalytic activity of the synthesized materials was evaluated using 10 ppm methylene blue (MB) under visible‐light irradiation for 120 min. The Cu 2 O/ZnO/PANI‐0.10 composite exhibited the highest MB degradation efficiency, reaching 90.01%. Due to the incorporation of PANI, the photoluminescence (PL) analysis confirmed that the intensity of Cu 2 O/ZnO/PANI photocatalysts was lower than that of the Cu 2 O/ZnO composite. The lowest PL intensity was Cu 2 O/ZnO/PANI‐0.10. It suggested a suppressed radiative recombination and more effective utilization of photogenerated charge carriers. Surprisingly, it was consistent with the highest MB degradation efficiency of this photocatalyst. The enhanced performance of the ternary composite was accompanied by improved photocatalyst reusability and structural stability. After three consecutive degradation cycles, the Cu 2 O/ZnO/PANI‐0.10 composite retained an MB degradation efficiency of 84.29%. Furthermore, FTIR and XRD analyses before and after the degradation cycles showed no significant changes in the chemical structure and crystalline phases of the composite. The improved photocatalytic performance suggests that the incorporation of ZnO and PANI can enhance the photocatalytic utilization of Cu 2 O in photocatalytic reactions.