Ceria (CeO₂) has emerged as a versatile material in catalytic systems, particularly in three-way catalysts (TWCs) for automotive exhaust. This review covers the fundamental properties, structural characteristics, redox behavior, and catalytic applications of CeO₂-based materials. Ceria's ability to shuttle between Ce(III) and Ce(IV) states, known as oxygen storage capacity (OSC), is crucial for its catalytic performance. The review discusses the structural evolution of CeO₂ in solid solutions with other oxides, such as zirconia (ZrO₂), and the impact of these interactions on catalytic properties. Computational studies have provided insights into the surface chemistry and defect formation in CeO₂, while experimental techniques like X-ray diffraction (XRD), Raman spectroscopy, and neutron diffraction have been used to characterize the materials. The review also highlights the emerging applications of CeO₂ in fuel cells, reforming processes, photocatalysis, and various catalytic reactions, emphasizing the material's potential for future market breakthroughs. Despite the extensive research, the redox properties of CeO₂ remain complex, and new techniques and theoretical methods are needed to fully understand and predict their behavior.Ceria (CeO₂) has emerged as a versatile material in catalytic systems, particularly in three-way catalysts (TWCs) for automotive exhaust. This review covers the fundamental properties, structural characteristics, redox behavior, and catalytic applications of CeO₂-based materials. Ceria's ability to shuttle between Ce(III) and Ce(IV) states, known as oxygen storage capacity (OSC), is crucial for its catalytic performance. The review discusses the structural evolution of CeO₂ in solid solutions with other oxides, such as zirconia (ZrO₂), and the impact of these interactions on catalytic properties. Computational studies have provided insights into the surface chemistry and defect formation in CeO₂, while experimental techniques like X-ray diffraction (XRD), Raman spectroscopy, and neutron diffraction have been used to characterize the materials. The review also highlights the emerging applications of CeO₂ in fuel cells, reforming processes, photocatalysis, and various catalytic reactions, emphasizing the material's potential for future market breakthroughs. Despite the extensive research, the redox properties of CeO₂ remain complex, and new techniques and theoretical methods are needed to fully understand and predict their behavior.