Layered double hydroxides: precursors for multifunctional catalysts

One-pot cascade reactions which involve multifunctional catalysts possessing different functions on the surface attract a growing interest. Relevant examples of the use of this type of catalysts in one-pot syntheses involving hydrogenation/dehydrogenation and aldol condensation reactions which give rise to valuable organic compounds are reported in this paper. It is shown that the layered double hydroxides (LDH) are precursors materials particularly adapted for the preparation of catalysts exhibiting acido/basic and redox sites. The paramount importance of the nature (Lewis or Bronsted) and the strength of the basic sites, as well as the nature of the metallic function of the supported metal catalysts obtained from LDH is discussed. It is emphasized on the equilibrium between the basic and metallic functions required to reach high activities and selectivities.