We have Zeolites!

Zeolites, also called molecular sieves, are crystalline microporous materials formed primarily by SiO₄ and AlO₄ corner-sharing tetrahedral building units that form three-dimensional (3D) frameworks with well-defined channels and cavities of molecular dimensions. The void space within the crystal allows zeolites to discriminate molecules based on their size or geometric shape. Read more on our Introduction to Zeolites blog.