A catalyst is the term for a chemical compound or substance that may speed up or slow down a chemical reaction without itself being changed or consumed at any time during the reaction. The process is similarly named as catalysis. Catalysts may vary, as a catalyst itself is not a specific type. In theory, almost anything could be a catalyst if it speeds up or slows down a reaction and is not consumed in the process. A few catalysts may be, but are not limited to, are: Electricity, Heat, and Pressure or any number of chemical compounds.
The best metals for making catalysts are platinum group metals, such as Rhodium and Platinum.