Several factors can lead to a decline in catalytic activity. These include:
Poisoning: The presence of impurities or contaminants can deactivate the catalyst. Common poisons include sulfur, lead, and carbon monoxide. Sintering: High temperatures can cause catalyst particles to agglomerate, reducing their surface area and, consequently, their activity. Coking: The deposition of carbonaceous materials on the catalyst surface can block active sites and hinder reactions. Leaching: The loss of active components from the catalyst due to interactions with the reaction medium, often observed in liquid-phase reactions. Structural Changes: Alterations in the catalyst's structure due to phase transformations or mechanical stress can reduce its effectiveness.
