Novel sol-gel synthesis of CeO2 nanoparticles using Morinda citrifolia L. fruit extracts: Structural and optical analysis

An efficient and eco-friendly sol-gel method using Morinda citrifolia L. fruit extracts as a weak base source, oxidizing, and capping agents were reported to synthesize cerium oxide nanoparticles (CeO2 NPs). CeO2 NPs exhibited the FCC crystal phase and the nanospherical shape with an average size of 51.6 nm. FT-IR characterization presented the absorption band of Ce–O at 705 cm−1 and the stretching vibration of N-H amine, which plays a crucial role in CeO2 NPs synthesis. The optical analysis revealed a strong optical absorption of CeO2 NPs at 351 nm with a bandgap value of 3.48 eV. Furthermore, the optical analysis of CeO2 NPs was further tested for the UV light absorption ability via methylene blue degradation. As a result, CeO2 NPs pointed out a low photocatalytic property with an efficiency of 10.25 and 9.46 % under UVA and UVB light irradiation for 15 h, respectively. Meanwhile, CeO2 NPs had good optical properties on their photoabsorption ability toward UVA and UVB light with an efficiency of 89.27 and 67.55 %, respectively.