## aggregate

in catalysis
Also contains definitions of: agglomerate in catalysis, primary particle in catalysis
https://doi.org/10.1351/goldbook.A00184
Certain materials used as catalysts or supports consist of spheroids smaller than $$10\ \text{nm}$$ in diameter, cemented into larger entities. A primary particle should be defined as the smallest discrete identifiable entity and the method of identification should be mentioned (e.g. @T06477@ @E02002@, scanning @E02002@). An assemblage of such primary particles exhibiting an identifiable collective behaviour (e.g. chemical nature of the aggregated primary particles, texture of the aggregate, @R05315@ to mechanical separation upon grinding) constitutes an aggregate. When describing the aggregates the criterion of identification should be mentioned. Strongly bonded aggregates are called agglomerates.
Source:
PAC, 1991, 63, 1227. (Manual on catalyst characterization (Recommendations 1991)) on page 1231 [Terms] [Paper]