Metal-Organic Framework Accelerated One-Step Capture and Reduction of Palladium to Catalytically Active Nanoparticles

Recovery of noble metals and in situ transforming to functional materials hold great promise in the sustainability of natural resources but remain as a challenge. Herein, the variable chemical microenvironments created by the inorganic-organic hybrid composition of metal-organic frameworks (MOFs) were exploited to tune the metal-support interactions, thus establishing an integrated strategy for recovering and reducing palladium (Pd). Assisted by sonic waves and alcoholic solvent, selective capture of Pd(II) from a complicated matrix to directly afford Pd nanoparticles (NPs) in MOFs can be achieved in one step within several minutes. Mechanism investigation reveals that the Pd binding site and the energy barriers between ionic and metallic status are sensitive to chemical environments in different frameworks. Thanks to the clean, dispersive, and uniform nature of Pd NPs, Pd@MOFs synthesized from a complicated environment exhibited high catalytic activity toward 4-nitrophenol reduction and Suzuki coupling reactions.