SYNTHESIS AND PHOTOCATALYTIC PROPERTIES OF CERIUM OXIDE IN THE DEGRADATION OF 2,4-DICHLOROPHENOXYACETIC ACID: INFLUENCE OF SYNTHESIS METHODS

Ceria (CeO2) was synthesized using three different methods: hydrothermal synthesis with water solvent and OH- agent, hydrothermal synthesis with ethanol solvent, and solvothermal synthesis. The synthesized materials were characterized using a range of advanced techniques, including Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-Ray Photoelectron Spectroscopy (XPS), and UV-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The photocatalytic activity of the synthesized CeO2 materials was evaluated through the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D), a common herbicide. The results indicated that CeO2 synthesized using the hydrothermal method with ethanol solvent had the smallest particle size, ranging from 35 to 55 nm. This small particle size is beneficial for photocatalytic applications as it provides a larger surface area for catalytic reactions. Consequently, this CeO2 material exhibited excellent photocatalytic activity, achieving a degradation efficiency of up to 54.14% for 2,4-D. Kinetic studies of the degradation process were conducted using a pseudo-first-order reaction model based on the Langmuir-Hinshelwood mechanism. These studies revealed that the degradation rate constants of 2,4-D on CeO2 catalysts synthesized by the different methods were quite similar, suggesting that the synthesis method primarily influences the particle size and surface properties rather than the intrinsic catalytic activity. These findings highlight the importance of optimizing synthesis methods to enhance the photocatalytic efficiency of CeO2 materials for environmental remediation applications. For citation: Nguyen Hoang Hao, Phung Thi Lan, Nguyen Thi Kim Giang, Cao Hoang Minh Chau, Nguyen Thi Thu Ha Synthesis and photocatalytic properties of cerium oxide in the degradation of 2,4-dichlorophenoxyacetic acid: influence of synthesis methods. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 4. P. 25-32. DOI: 10.6060/ivkkt.20256804.7128.