Several factors contribute to transportation delays in catalytic systems:
1. Diffusion Limitations: The rate of diffusion of reactants to the catalytic sites can be slower than the rate of reaction, leading to a buildup of reactants in the bulk phase. 2. Mass Transfer Resistance: In heterogeneous catalysis, the transfer of reactants from the bulk phase to the catalyst surface and the removal of products can encounter resistance, causing delays. 3. Pore Diffusion: For porous catalysts, the internal diffusion of reactants within the catalyst pores can be slower than the reaction rate, creating internal mass transfer limitations.
