Perovskites as Substitutes of Noble Metals for Heterogeneous Catalysis: Dream or Reality

The paper focuses on providing information about the latest advances in development and application of perovskites in heterogeneous catalytic processes. Synthesis methods of perovskites have rapidly achieved great success since their first preparation from the simple ceramic method in the 1970s. Several new synthesis routes classified as solution-mediated methods have been developed from the 1980s, including coprecipitation, complexation, sol-gel, and freeze/spray drying. Coprecipitation is used to reduce the total amount of residual carbonate with the aim of reducing the required calcinations temperature. The rate of evaporation is increased using freeze drying, allowing synthesis of solids with quite high surface areas. Another popular solution-mediated route is the sol-gel method, which is based on hydrolysis of precursors such as alkoxides, nitrates, carboxylates, acetylacetonates, chlorides, and other inorganics to generate a homogeneous solution and transforming it into a gel by densification or subsequent heat treatment.