Preparation and catalytic properties of Pd nanoparticles supported on micro-crystal DUT-67 MOFs

Abstract

Zr-based MOFs usually feature exceptionally high thermal and chemical stability, which suggests that composites of noble metals and Zr-based MOFs could have wide industrial applications. In this work, we report the synthesis and characterization of Pd nanoparticles (of three different loadings: 0.3%, 0.5% and 1.0%) supported on micro-crystal DUT-67 MOFs. Via SEM, TEM and XPS characterization methods, it was found that the Pd nanoparticles were well dispersed on the interface of the MOF micro-crystals, with a diameter of 3.5 nm, and both the dangling organic groups and the cavities of the MOFs play important roles. Furthermore, PXRD, IR, TGA and N₂ adsorption measurements confirmed that the composites are very robust. Studies on the catalytic properties indicated that they have good catalytic performance with a conversion of 99% and selectivity of 89% in the Suzuki coupling reaction. By a series of explorations, we found the best catalytic conditions are an ethanol–water mixed solvent as the medium, K₂CO₃ as the base and a temperature of 70 °C. Moreover, good catalytic properties were also shown for the hydrogenation of nitrobenzene, where the optimum temperature was 60 °C, and a conversion of 99% and selectivity of 99% were achieved.