Several factors can lead to a reduced surface area in catalysts:
1. Sintering: This is the process where particles of the catalyst aggregate at high temperatures, leading to a decrease in surface area. Sintering can occur due to prolonged exposure to high temperatures during reaction processes.
2. Coking: In carbon-based reactions, the deposition of carbonaceous materials (coke) on the surface can block active sites, effectively reducing the available surface area.
3. Poisoning: Certain contaminants or impurities can adsorb onto the catalyst's surface, decreasing the number of active sites. Common poisons include sulfur compounds and heavy metals.
4. Mechanical Attrition: Physical wear and tear during the catalytic process can lead to the breakdown of the catalyst structure, reducing its surface area.
