Cerium oxide is widely used as a polishing agent in the glass and semiconductor industries. It is highly effective in chemical-mechanical planarization (CMP) processes, where it helps achieve smooth, scratch-free surfaces on silicon wafers and optical glass. Its ability to remove material through both mechanical abrasion and chemical reaction makes it ideal for precision polishing.

In the glass manufacturing industry, cerium oxide is employed as a UV absorber and decolorizer, helping to prevent discoloration when exposed to sunlight over long periods.

In automotive engineering, cerium oxide is added to diesel fuels to improve combustion efficiency and reduce soot emissions. It acts as a combustion catalyst, promoting more complete fuel burning and lowering particulate matter in exhaust gases.

It is also used in catalytic converters to reduce harmful emissions from vehicles. Cerium oxide can store and release oxygen depending on environmental conditions, which helps maintain optimal oxygen levels for converting pollutants like carbon monoxide and nitrogen oxides into less harmful substances.

In the field of materials science, cerium oxide is incorporated into coatings and ceramics for its thermal stability and resistance to oxidation. It enhances durability in high-temperature applications such as furnace linings and heat-resistant coatings.

Additionally, it is used in solid oxide fuel cells as an electrolyte material due to its excellent oxygen ion conductivity at high temperatures, supporting clean energy production.

Cerium oxide shows promise in biomedical and cosmetic applications, including antioxidant and anti-inflammatory treatments, as well as in skincare products like sunscreens, where it helps neutralize reactive oxygen species and protect against UV-induced damage.