Solution infiltration of palladium into MOF-5: synthesis, physisorption and catalytic properties

Abstract

Palladium was infiltrated into the highly porous metal–organic framework MOF-5 {[Zn₄O(bdc)₃], bdc = benzene-1,4-dicarboxylate} using [Pd(acac)₂] (acac = acetylacetonate) as the precursor in chloroform solution via ‘incipient wetness’ impregnation. The specific surface area decreases from 2885 m² g⁻¹ to 958 m² g⁻¹ after infiltration. After reduction in hydrogen or under vacuum, the hydrogen adsorption capacity is increased from 1.15 wt% to 1.86 wt% at 1 atm and 77 K. The palladium loaded MOF-5 has a high catalytic activity in styrene hydrogenation comparable to that of palladium on activated carbon, but cis-cyclooctene hydrogenation is considerably slower. Even at room temperature, the catalyst is not stable in air due to the low hydrothermal stability of the MOF-5 support.