A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism.

Does a catalyst speed up?

CatalysisA catalyst speeds up a reaction by lowering the activation energy required for the reaction to proceed.

Can catalyst decrease the speed of reaction?

Catalysts can lower the activation energy and increase the reaction rate without being consumed in the reaction. ... Molecules joined by stronger bonds will have lower reaction rates than will molecules joined by weaker bonds, due to the increased amount of energy required to break the stronger bonds.