mesopore in catalysis

Pore of intermediate size. [Those with widths exceeding about $0.05 µm$ or $50 nm$ ( $500 Å$ ) are called macropores; those with widths not exceeding about $2 nm$ ( $20 Å$ ) are called micropores].

Source:

PAC, 1972, 31, 577 (Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry) on page 585

PAC, 1976, 46, 71 (Manual of Symbols and Terminology for Physicochemical Quantities and Units - Appendix II. Definitions, Terminology and Symbols in Colloid and Surface Chemistry. Part II: Heterogeneous Catalysis) on page 79