Metallic and bimetallic nanocatalysts incorporated into highly porous coordination polymer MIL-101

This paper reports the development of a facile, general and effective approach, based on microwave irradiation (MWI), for the incorporation of a variety of metallic and bimetallic nanoparticle catalysts within the highly porous coordination polymer MIL-101. The current approach is based on the simultaneous activation of the pores of MIL-101 and the rapid chemical reduction of metal precursors using MWI in the presence of a reducing agent. Small Pd, Cu and Pd-Cu nanoparticles of 2-3 nm are incorporated within the pores and larger particles of 4-6 nm are supported on the surface of the MIL-101 crystals. TEM images reveal that the loading of the particles using MWI is uniform across the MIL crystals. The observed catalytic activities toward CO oxidation of the Pd nanocatalysts supported on the highly porous MIL-101 polymer are significantly higher than any other reported metal clusters supported on metal-organic frameworks. The observed high activity is attributed to the small metal nanoparticles imbedded within the pores of the MIL crystals. The activity of the small embedded particles is higher than those supported on the surface. This allows the use of small metal loadings for efficient low temperature CO oxidation. These results should allow optimization of a new class of nanocatalysts incorporated within the highly porous MIL-101. These materials are promising environmentally relevant catalyst systems.