Deactivation of Catalysts One of the primary reasons for efficiency reduction is the deactivation of catalysts. Over time, catalysts can lose their activity due to poisoning, fouling, sintering, or loss of active sites. Poisoning occurs when a foreign substance binds strongly to the active sites of the catalyst, hindering the reaction. Fouling, on the other hand, involves the deposition of unwanted materials on the catalyst surface, obstructing the active sites.
Thermal Degradation Thermal degradation is another significant factor. Catalysts often operate under high-temperature conditions, which can lead to structural changes and loss of active surface area. This degradation can be mitigated by using thermal stabilizers or designing catalysts with higher thermal stability.
Mass Transfer Limitations Efficiency can also be reduced due to mass transfer limitations. In heterogeneous catalysis, the reactants must diffuse to the catalyst surface, and the products must diffuse away. Poor mass transfer can limit the reaction rate, especially in porous catalysts where the diffusion path is longer. Optimizing the pore structure and using supports with high surface areas can help address this issue.
