[scientizscht (OP)]

Hello

Let's say we immerse a particle of catalyst in a solution of a reactant.

As the catalyst converts the reactant, it creates a concentration gradient around the particle that is replenished.

How can I calculate the minimum diffusion coefficient so that the reaction is not inhibited from inadequate replenishment of the reactant around the catalyst?

Thanks!

[Bored chemist]

It is going to vary with the catalyst, the particle size, teh temperature, the concentration and probably other things too.

The actual answer to your question, as asked
"How can I calculate the minimum diffusion coefficient"
is learn physical chemistry.

[evan_au]

...or you could just stir the mixture, and not rely on passive diffusion.