Synthesis Modulation as a Tool To Increase the Catalytic Activity of Metal–Organic Frameworks: The Unique Case of UiO-66(Zr)
Frederik Vermoortele, Bart Bueken, Gaëlle Le Bars, Ben Van de Voorde, Matthias Vandichel, Kristof Houthoofd, Alexandré Vimont, Marco Daturi, Michel Waroquier, Véronique Van Speybroeck, Christine E. A. Kirschhock, Dirk De Vos
Abstract
The catalytic activity of the zirconium terephthalate UiO-66(Zr) can be drastically increased by using a modulation approach. The combined use of trifluoroacetic acid and HCl during the synthesis results in a highly crystalline material, with partial substitution of terephthalates by trifluoroacetate. Thermal activation of the material leads not only to dehydroxylation of the hexanuclear Zr cluster but also to post-synthetic removal of the trifluoroacetate groups, resulting in a more open framework with a large number of open sites. Consequently, the material is a highly active catalyst for several Lewis acid catalyzed reactions.