Precious metal catalysts are also termed “noble metal catalysts”, showing unique characteristics in our lives. They possess an incompletely filled d-orbital to lend electrons or withdraw electrons from the reagent, depending on the nature of the reaction. Hence, precious metals always show high activity and selectivity in catalysis. Apart from this, precious metal catalysts are also stable and are not easily form oxides by oxidation. Not only high activity but also high thermal stability of precious metal catalysts allows us to use precious metal catalysts for wide range of applications, such as pharmaceuticals, agrochemicals, petrochemicals, chemicals, environment and material sciences.