microporeuses

Microporeuses, or microporous materials, are solids that contain a network of pores with diameters below about 2 nanometers. This microporosity yields very high internal surface area and enables selective adsorption of small molecules. Microporous materials are distinguished from mesoporous (2–50 nm) and macroporous (>50 nm) types.

Common examples include zeolites, which are crystalline aluminosilicates with well-defined pore systems; activated carbons, which are amorphous carbon rich in micropores; silica-based materials such as amorphous silica with microporosity; and modern classes like metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) that offer tunable pore sizes. Natural microporous minerals, such as certain clays and zeolitic rocks, also play a role in various applications.

Key properties of microporeuses include very high surface areas, often exceeding 1,000 square meters per gram, along with shape-selective adsorption and relatively fast diffusion for small molecules. The pore size distribution influences selectivity for gas separations and catalysis. Stability varies by material class; zeolites are typically highly thermally and chemically stable, while MOFs and COFs show a broader range of stability.

Applications span gas storage and separation (hydrogen, carbon dioxide, methane), carbon capture, purification of hydrocarbons, catalysis as catalyst supports, environmental remediation, and energy storage in devices like supercapacitors. Characterization relies on gas adsorption measurements (for example, nitrogen at 77 K) to obtain BET surface area and pore-size distributions, while micropore volumes can be evaluated by methods such as t-plot or the Dubinin–Radushkevich equation. Synthesis approaches include hydrothermal or solvothermal routes for zeolites, chemical activation and pyrolysis for carbons, and self-assembly for MOFs and COFs.