bifunctional catalysis

Catalysis (usually for hydron transfer) by a bifunctional chemical species involving a mechanism in which both functional groups are implicated in the rate-controlling step, so that the corresponding catalytic coefficient is larger than that expected for catalysis by chemical species containing only one of these functional groups. The term should not be used to describe the concerted action of two different catalysts ('concerted catalysis').
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1089