The key difference between catalyst promoter and catalyst poison is that catalytic promoters can increase the effectiveness of the catalyst, whereas catalyst poison can decrease the effectiveness of the catalyst.
Catalysts and inhibitors are chemical compounds. These two groups of compounds show opposite activity in biological and chemical systems. They participate in chemical reactions but are not consumed. A catalyst is a chemical compound that can increase the rate of a reaction without being consumed. Therefore, this compound can continue to act repeatedly. Due to this reason, only a small amount of catalyst is required for a certain chemical reaction.
Typically, a catalyst provides an alternative pathway for a chemical reaction by reducing the activation energy of a reaction. Therefore, the catalyst combines with the reactant to create an intermediate product; after the completion of the required reaction, the catalyst leaves the intermediate and regenerates.
CONTENTS
1. Overview and Key Difference
2. What is a Catalyst Promoter
3. What is a Catalyst Poison
4. Catalyst Promoter vs Catalyst Poison in Tabular Form
5. Summary – Catalyst Promoter vs Catalyst Poison
What is a Catalyst Promoter?
A catalyst promoter is a substance that can increase the efficiency of a catalyst. Usually, this substance is mixed with the catalyst-containing chemical reaction mixture to make it more effective. Catalyst promoters simply help to improve the overall chemical reaction. Moreover, a catalyst promoter shows no or little catalytic effect or its properties.
Figure 01: Harber’s Cycle
For example, molybdenum or a mixture of potassium and aluminum oxides in Harber’s cycle acts as promoters for catalysts. Typically, the catalyst is added to the reaction mixture at the beginning of the chemical reaction, while the catalyst promoter is added during the reaction to increase the efficiency.
What is a Catalyst Poison?
A catalyst poison is a substance that can reduce the effectiveness of a catalyst. Therefore, it acts as an inhibitor for the catalyst and the chemical reaction in which it is involved. Theoretically, catalysts are not consumed during a chemical reaction. Therefore, the role of catalyst poison is only to reduce the effect shown by the catalyst in the chemical reaction. Sometimes, catalyst poison compounds can decrease the reaction rate or can completely destroy the reaction process.
As a common example, the platinum catalyst that is useful in the oxidation of hydrogen can be poisoned using carbon monoxide as a catalyst poison. Similarly, we can use hydrogen sulfide or carbon monoxide to destroy the activity of iron catalysts in Harber’s process.
What is the Difference Between Catalyst Promoter and Catalyst Poison?
A catalyst is a chemical compound that can increase the rate of a reaction without itself being consumed. There are promoters and poisons for catalysts. The key difference between catalyst promoter and catalyst poison is that catalytic promoters can increase the effectiveness of the catalyst, whereas catalyst poison can decrease the effectiveness of the catalyst. If we consider examples of catalyst promoters and poisons, molybdenum or a mixture of potassium and aluminum oxides in Harber’s cycle acts as promoters for catalysts, while the platinum catalyst that is useful in the oxidation of hydrogen can be poisoned using carbon monoxide as a catalyst poison.
The below infographic presents the differences between catalyst promoter and catalyst poison in tabular form for side by side comparison.
Summary – Catalyst Promoter vs Catalyst Poison
There are two types of compounds that can affect the activity of a catalyst: catalyst promoters and catalyst poison. The key difference between catalyst promoter and catalyst poison is that catalytic promoters can increase the effectiveness of the catalyst, whereas catalyst poison can decrease the effectiveness of the catalyst.
Reference:
1.”Promoter | Catalyst.” Encyclopedia Britannica.
Image Courtesy:
1. “Born-haber cycle LiF” By Jkwchui – Own work (CC BY-SA 3.0) via Commons Wikimedia