Chemical Modification: This involves altering the chemical structure of the catalyst to enhance its performance. For example, adding promoters like alkali metals can increase the activity of metal catalysts. Physical Treatment: Techniques like calcination (heating in the presence of air or oxygen) can change the physical properties of the catalyst, such as surface area and pore size, thereby improving its activity. Incorporation of Promoters: Adding small amounts of other substances (promoters) can enhance the activity of a catalyst. For instance, the addition of rare earth elements can improve the catalytic activity and stability.
