Catalysts are the unsung heroes of the chemical reactions that keep human civilization running. A catalyst is a substance that accelerates chemical reactions. Molecules that would normally take years to interact can now do so in seconds owing to the assistance of a catalyst. Catalytic materials are materials that allow the reaction to occur quickly and efficiently. Oxides, composite oxides and salts, sulphides, carbides, halides and unsupported and supported metals are all taken into account. Catalytic materials can be found in a variety of forms and can be used in a variety of ways, including different schemes and procedures.