Catalytic Promoter

In a chemical reaction, when a substance is added to a solid catalyst to boost the rate of the reaction, that substance is called a promoter. A promoter in catalyst does not have a catalytic effect. Sometimes it interacts with the other components to change their chemical effect on the substance that had already catalyzed them. This interaction leads to changes in the crystal or electronic structures of the solid components.

Oxidising and reducing gases or liquids, metallic oxide catalyst, metallic ions are added to the catalyst or reaction before they are used. Examples of some promoters or activators are- during the manufacture of methyl alcohol, chromic oxide is used as a promoter from the water gas including catalyst zinc oxide. Similarly, when a little amount of molybdenum is added to finely divided iron, it increases the process of synthesis of ammonia and here molybdenum acts as a catalyst.

Difference Between Catalyst and Promoter

A catalyst is a material that does not change itself when the rate of the chemical reaction is increased. It participates in the reaction but does not react itself. A promoter, on the other hand, is a substance that helps in increasing the action of a catalyst. It does not have any catalytic value of itself.

For example, in the case of Haber's process, iron acts as a catalyst. When molybdenum is added to it, the efficiency of iron increases. Here, molybdenum acts as a promoter.

Difference Between Catalyst and Catalysis

The only difference between catalyst and catalysis is that a catalyst is a material that accelerates a chemical reaction but does not change itself and does not get it involved in the overall reaction whereas catalysis is the process of changing the rate of the reaction by involving a catalytic material in it.

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Promoter and Catalyst Poison 

Let us now go through the difference between catalyst promoter and catalyst poison. The substance that destroys the catalyst activity only by its presence is called catalytic poison. For example, a small amount of arsenic oxide, if present in the reacting gas, will reduce platinized asbestos activity that is used as a catalyst for the manufacture of sulphuric acid.

Similarly, the presence of sulphuric acid or carbon dioxide will destroy the catalytic activity of iron in the synthesis of ammonia by Haber's process. Likewise, the presence of carbonic oxide in the platinum catalyst is used in the oxidation of hydrogen.

By increasing the temperature, the catalytic power of the catalyst will increase but after attaining a certain temperature its power will start decreasing. So, at a particular temperature, the catalytic activity of a catalyst will become maximum. This temperature is known as optimum temperature.

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Catalytic Promoters

To explain catalytic promoters, it is important to understand that a catalytic promoter is a material that is mixed with catalysts in small quantities to increase the efficiency of the catalyst. In other words, it helps to enhance the chemical reaction. These are also known as activators.

The promoters in catalyst increase the surface area stabilization that is present against crystal growth mechanical strength and sintering.

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Catalyst Promoter Definition

The catalyst usually works by giving an alternative way for the chemical reaction to occur. This reduces the activation energy by increasing the reaction rate. A catalyst promoter acts as an accelerator for the catalysts but it is not a catalyst by itself.

Catalysts are of Two Types: a positive catalyst that fastens the chemical reaction and a negative catalyst that slows down the reaction rate.

According to the theory of collision reaction, an effective collision occurs between the reacting molecules. For effective collision, the molecules must have a minimum amount of energy that is called activation energy to form activated complexes that mix to give product molecules. The catalyst gives a new way that contains a small amount of activation energy. So, the maximum number of effective collisions occurs in presence of a catalyst at the same temperature without a catalyst. So, a catalyst is highly essential to make the reaction faster.