Tuning the hydrogenation activity of Pd NPs on Al–MIL-53 by linker modification?

Catalysis Science & Technology Pub Date: 2013-12-19 DOI: 10.1039/C3CY00910F

Abstract

The hydrogenation activity of 3 wt.% Pd nanoparticles supported on various mono-group (H, OCH3, NH2, Cl, and NO2) substituted Al–MIL-53 materials has been investigated. Substituents enhanced the dispersion of palladium nanoparticles on Al–MIL-53, leading to a narrow particle size distribution in the range of 2 to 4 nm. Pd nanoparticles on fresh catalysts were present as a mixture of Pd(II) and Pd(0) with different ratios. These Pd species readily became metallic in a hydrogen flow even at room temperature. Their activities in hydrogenation of phenol and phenylacetylene are linked to the substituents on the aromatic ring of the framework. Catalysts with electron-donating groups (OCH3 and NH2) show much higher activity than those containing electron-withdrawing groups (Cl and NO2). This behavior might be explained by the hydrogen dissociation abilities of metallic Pd nanoparticles affected by the organic linkers.

Graphical abstract: Tuning the hydrogenation activity of Pd NPs on Al–MIL-53 by linker modification
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