Applications of perovskites as catalysts

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Perovskite-type composite oxides ABO3 are a new type of inorganic non-metallic material with unique physical and chemical properties. The A site is generally occupied by rare earth or alkaline earth element ions, while the B site is occupied by transition element ions. Both the A and B sites can be partially replaced by other metal ions with similar radii without significant changes to their crystal structure; therefore, theoretically, they are ideal specimens for studying catalyst surfaces and catalytic performance. Due to their stable crystal structures, unique electromagnetic properties, and high activities in redox, hydrolysis, isomerization, electrocatalysis, and other processes, these compounds possess great potential as novel functional materials for applications in environmental protection and industrial catalysis. 　　Perovskite composite oxides possess unique crystal structures; in particular, the crystal defect structures and properties that arise as a result of doping make them suitable for use, or potentially applicable, in various fields such as solid fuel cells, solid electrolytes, sensors, high-temperature heating materials, solid resistors, and redox catalysts that can replace precious metals. They have thus become a focus of research in fields such as chemistry, physics, and materials science. By replacing or partially replacing the A or B sites in standard perovskites with other metal ions, various composite oxides can be synthesized, resulting in anionic defects or B-site ions with different valence states. These compounds represent a new class of functional materials with excellent properties and wide-ranging applications. Research is already underway on using perovskites for converting vehicle exhaust gases.