What is difference between catalyst and promoter?
In chemistry, a catalyst (Greek: καταλύτης, catalytēs) is a substance that decreases the activation energy of a chemical reaction (see also catalysis) without itself being changed at the end of the chemical reaction. Catalysts participate in reactions but are neither reactants nor products of the reaction they catalyse (a strange ‘exception’ is the process of autocatalysis). They work by providing an alternative pathway for the reaction to occur, thus reducing the activation energy and increasing the reaction rate. More generally, one may at times call anything that accelerates a reaction, without itself being consumed or changed, a “catalyst” (for example, a “catalyst for political change”). A promoter is an accelerator of catalysis, but not a catalyst by itself. An inhibitor inhibits the working of a catalyst.
