of a catalyst
The distribution in space of the atoms or ions in the material part of the catalyst and, in particular, the distribution at the surface.
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