A promoter is a substance that enhances the activity of a catalyst without being catalytically active itself. Promoters act as supportive agents by increasing the efficiency or selectivity of a chemical reaction. They are an important component of many industrial processes that utilize catalysts.

Function of a promoter

1. Improved catalyst performance: Increases the reaction rate or reduces the required activation energy.
2. Increased selectivity: Promotes the formation of a desired product and reduces side reactions.
3. Catalyst stabilization: Prevents deactivation of the catalyst by heat, pressure, or impurities.
4. Surface optimization: Changes the physical or chemical properties of the catalyst, e.g. by increasing the active surface area.