Green synthesis of CeO2 NPs using Manilkara zapota fruit peel extract for photocatalytic treatment of pollutants, antimicrobial, and antidiabetic activities

Here, we have synthesized CeO2 NPs using Sapodilla fruit (Manilkara zapota) peel (SFP) extract via a green approach. The synthesized SFP extract-CeO2 NPs were characterized by powder XRD, TEM, UV-vis DRS, PL, FTIR, and TGA techniques. CeO2 NPs and SFP extract-CeO2 NPs were confirmed by UV-vis spectra at the strong absorption peak at 400-435 nm and the calculated optical band gaps were well matched. The FT-IR spectra of CeO2 NPs reveal that the presence of carboxyl and amide groups in the SFP extract is confirmed and these are responsible for the bio-reduction of Ce ions into CeO2 NPs. From XRD, the average crystallite size of the SFP extract-CeO2 NPs is 10 +/- 1.5 nm was observed, which is a good agreement with TEM analysis. The synthesized CeO2 NPs performed an excellent photodegradation of several dyes and antibiotics in aqueous solutions within 18 min of reaction under UV-visible irradiation. The synthesized SFP extract-CeO2 NPs show good antimicrobial activity against several pathogens (bacteria and fungi) using a paper disc method other than CeO2 NPs. In addition, the antidiabetic activity of SFP extract-CeO2 NPs is significantly inhibited by both a-amylase and a-glucosidase enzymes with IC50 values when compared with the standard (acarbose).