Is it true that internal diffusion necessarily occurs in porous materials? Does internal diffusion not exist in non-porous materials?

Thread Content

6. Chemical reactions and transport phenomena in multiphase systems 6.1 Steps in the process of multiphase catalytic reactions 6.1.1 Macroscopic structure and properties of solid catalysts 6.1.2 Process steps 6.2 Mass and heat transfer between the fluid and the outer surface of catalyst particles 6.2.1 Transfer coefficients 6.2.2 Concentration and temperature differences between the fluid and the particle surface 6.2.3 Influence of external diffusion on multiphase catalytic reactions 6.3 Diffusion of gases in porous media 6.3.1 Pore diffusion 6.3.2 Diffusion within porous particles 6.4 Diffusion and reaction in porous catalysts 6.4.1 Concentration distribution of reactants within porous catalysts 6.4.2 Effective factor for internal diffusion 6.4.3 Effective factor for internal diffusion in non-first-order reactions 6.4.4 Effective factor when both internal and external diffusion are involved 6.5 Influence of internal diffusion on the selectivity of composite reactions 6.6 Determining the influence of diffusion in multiphase catalytic reactions 6.6.1 Determining the influence of external diffusion 6.6.2 Determining the influence of internal diffusion 6.7 Kinetic illusions under diffusion interference Main references Is internal diffusion always associated with porous materials? Does internal diffusion not exist in materials that are not porous?