Eco-efficient synthesis of cerium oxide nanoparticles via combustion method: enhanced their photocatalytic, and electrochemical properties

This study explores the enhancement of methylene blue (MB) dye degradation by using cerium oxide nanoparticles (CeO₂ NPs) that have been green synthesized, with Cleome gynandra seed extract acting as natural reducing and stabilizing agents. Green synthesis provides a sustainable and environmentally friendly alternative to conventional methods for producing CeO₂ NPs, thereby decreasing harmful environmental impacts. To enhance their performance in dye degradation and electrochemical applications, the synthesized NPs were further optimized. The X-ray diffraction (XRD) pattern indicated the face-centered cubic structure of CeO₂-NPs, which had a crystallite size of around 34.12 nm. The scanning electron microscopy (SEM) studies revealed the spherical form of CeO₂ nanoparticles. The UV–Visible spectroscopy revealed a band gap of 3.2 eV, which is suitable for absorption in the UV region. The bio-synthesized CeO₂-NPs demonstrated a superior photocatalytic decolorization efficiency by exhibiting 94% methylene blue (MB) dye degradation efficiency after exposure to UV light at 180 min. Further, the reusability experiment reveals better photostability of CeO₂ NPs. Additionally, the cyclic voltammetry (CV) analysis of the CeO₂ demonstrated remarkable bio-analyte sensing abilities by presenting significant oxidation and reduction peaks towards paracetamol sensing. Electrochemical impedance spectroscopy (EIS) presented significant findings into the ionic conductivity of a material and the capacitive performance of the CeO₂-modified electrode.