Catalyst deactivation refers to the process where a catalyst loses its effectiveness in facilitating a chemical reaction. This can occur due to various factors, such as poisoning, where unwanted substances bind to the catalyst's active sites, or sintering, where the catalyst particles agglomerate and reduce their surface area. Deactivation can significantly impact industrial processes, leading to decreased efficiency and increased costs. To mitigate this, methods like regeneration or replacement of the catalyst are often employed. Understanding catalyst deactivation is crucial in fields like chemical engineering and petrochemistry to maintain optimal reaction conditions.