Contaminants can affect catalysts in several ways:
Poisoning: Certain contaminants, such as sulfur or lead, can adsorb strongly onto the active sites of catalysts, rendering them inactive. This is known as catalyst poisoning. Fouling: Physical deposition of contaminants on the surface of a catalyst can block active sites, reducing the available surface area for reactions. Sintering: High temperatures can cause contaminants to induce sintering, where small catalyst particles agglomerate into larger particles, decreasing their surface area and activity. Leaching: Some contaminants can cause the active components of a catalyst to dissolve and be washed away, leading to a loss of catalytic material.
