| Abstract Scope |
Cerium oxide (CeO₂) nanoparticles have emerged as versatile semiconductor photocatalysts because of their unique fluorite crystal structure, reversible Ceł⁺/Ce⁴⁺ redox chemistry, and exceptional oxygen-storage capacity. However, the relatively wide band gap of pristine CeO₂ restricts efficient utilization of visible light, thereby limiting its photocatalytic performance under solar irradiation. Oxygen vacancy engineering has recently become one of the most effective strategies for overcoming this limitation by introducing localized electronic states, enhancing visible-light absorption, promoting charge separation, and facilitating adsorption and activation of oxygen and water molecules. Oxygen vacancies simultaneously regulate Ceł⁺ concentration, reactive oxygen species (ROS) generation, and surface catalytic activity, making them fundamental active sites for photocatalytic reactions. This mini-review critically discusses the mechanistic role of oxygen vacancies in visible-light photocatalysis, recent advances in vacancy engineering, photocatalytic applications for environmental remediation, current challenges, and future research directions toward rational defect-controlled photocatalyst design. |