The medium can affect catalytic activity in several ways:
Influence on Catalyst Structure
The medium can induce changes in the structure of the catalyst, including its oxidation state, morphology, and dispersion. For example, the presence of water can lead to the hydration or hydrolysis of certain catalysts, altering their activity.
Impact on Reaction Mechanism
The medium can stabilize different intermediates and transition states, potentially changing the reaction mechanism. For example, protic solvents can donate hydrogen bonds, stabilizing certain intermediates more than others.
Effect on Mass Transfer
The medium can enhance or impede the diffusion of reactants and products to and from the catalyst surface. In gas-phase reactions, the medium can provide rapid mass transfer, while in liquid-phase reactions, the viscosity of the solvent can play a significant role.
