Biosynthesis of ZnO-CeO2-Ag2O nanocomposite with Ocimum basilicum L seed extract as a highly efficient photocatalyst and assessment of their anticancer effects

[Display omitted] •A green procedure for the synthesis of ZnO-CeO2-Ag2O nanocomposite using Ocimum Basilicum L Seed extract.•ZnO-CeO2-Ag2O nanocomposite as an excellent photocatalyst for the degradation of organic dyes.•Low cell toxicity of the ZnO-CeO2-Ag2O nanocomposite on cancer Huh-7 cell line. Ternary nanocomposites have received attention in recent years due to their unique properties and wide applications, especially in the field of photocatalysis and medicine. This study reports photocatalytic activity and cytotoxicity of ZnO-CeO2-Ag2O nanocomposite which was successfully synthesized using the green method with Ocimum basilicum L (OBL) seed extract for the first time. XRD analysis showed that the crystallinity size of the synthesized nanocomposite increased from 34.11 nm (400 °C) to 39.32 nm (600 °C) with increasing calcination temperature. The morphology of the nanocomposite with an almost spherical (with average diameters of ∼20–24 nm) appearance was confirmed by FESEM and TEM images. The DRS analysis showed that with increasing temperature, the value of the band gap decreased from 3.38 eV (400 °C) to 3.33 eV (600 °C). The degradation percentage of dyes using nanocomposite in the photocatalytic process was 93.81 % for methylene blue (MB) in optimal conditions (pH=10, concentration of catalyst = 2 × 10−3 M, and concentration of MB = 10−5 M) and 97.44 % for Rhodamine B (RhB, pH = 2) during 105 min. The anticancer effects of the nanocomposite were studied on degrading the Huh-7 cell, and the IC50 value was reported about 338.2 μg/mL.