Cerium oxide is an inorganic substance with a chemical formula of CeO2, a light yellow or yellowish brown auxiliary powder. Density 7.13g/cm3, melting point 2397ºC, insoluble in water and alkali, slightly soluble in acid. At a temperature of 2000 °C and a pressure of 15MPa, cerium oxide can be obtained by reducing cerium oxide with hydrogen. When the temperature is free at 2000 °C and the pressure is free at 5MPa, the cerium oxide is yellowish, slightly reddish, and pink. Its performance It is used as polishing material, catalyst, catalyst carrier (auxiliary), ultraviolet absorber, fuel cell electrolyte, automobile exhaust gas absorber, electronic ceramics, etc.