One-step encapsulation of Pd nanoparticles in MOFs via a temperature control program

Abstract

The control over the size and location of metal nanoparticles (MNPs) within metal–organic frameworks (MOFs) is achieved in one step through a cooperative in situ metal precursor incorporation and on-site moderate reduction process, which is operated by a temperature control program. The choice of operation temperatures is based on the MOF assembly temperature (T₁), and an elevated temperature (T₂) to elicit the reducibility of DMF solvent to fabricate MNPs. Such a rational design could effectively introduce metal precursors into the pores of MOFs and on-site moderately reduce the embedded metal ions to generate tiny MNPs by the penetrated DMF, which could not be achieved by a quick heating process. The proposed methodology has been successfully applied to the one-step fabrication of ultrafine Pd NPs selectively encapsulated inside the pores of UiO-67 without any external reducing agents. The obtained Pd-in-UiO-67 shows superior catalytic activity and selectivity in the hydrogenation of styrene even at room temperature and atmospheric pressure of H₂.