Cerium Oxide Nanoparticles: A Tiny Solution for Big Challenges

Cerium oxide nanoparticles (CeO 2 NPs) have emerged as promising materials owing to their unique redox activity, oxygen vacancy defects, and high surface area, which enable versatile functionalities. This review summarizes the major advances in their synthesis methods, including conventional physical and chemical techniques as well as sustainable green approaches. The structural and physicochemical features of CeO 2 NPs are correlated with their wide‐ranging applications in environmental remediation, biomedicine, agriculture, and energy technologies. Particular emphasis is given to their roles in catalysis, wastewater treatment, antimicrobial activity, biosensing, crop protection, and energy storage. The review also highlights emerging opportunities such as nanozyme activity, luminescence‐based sensing, and bioimaging. Finally, current limitations and future research directions are outlined to enhance performance, biocompatibility, and scalability. The insights provided aim to guide the rational design of CeO 2 nanomaterials for next‐generation sustainable applications.