High Quality Content by WIKIPEDIA articles! The catalyst is a substance, usually used in small amounts relative to the reactants, that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. One or more kinds of catalysts can be loaded on another material with a high surface area, which serves as the support, to form a supported catalyst as a whole system. In a supported catalyst system, the significance of using the support are to increase the dispersion of the active phases, to have a better control of the porous structure, to improve mechanical strength, to prevent sintering and to assist catalysis. There is a wide spectrum of supports ranging from conventional and most commonly alumina to novel various kinds of activated carbon. Synthesis methods and functions vary greatly due to different kinds of support and catalytic materials.