Bimetal–organic frameworks for functionality optimization: MnFe-MOF-74 as a stable and efficient catalyst for the epoxidation of alkenes with H₂O₂

Abstract

In this work, we synthesized a series of microcrystalline Mn_xN_100-x-MOF-74 (N = Fe, Co and Ni) materials by a one-pot reaction. Powder X-ray diffraction (PXRD) patterns of Mn_xN_100-x-MOF-74 matched well with those of single-metal MOF-74, and the scanning electron microscopy (SEM) images exhibited homogeneous nanocrystallites aggregated together. The amounts and dispersion of metals were analyzed by using inductively coupled plasma (ICP) and energy-dispersive X-ray spectroscopy (EDS), separately. Mn_xN_100-x-MOF-74 could remain crystalline and efficiently catalyze the epoxidation of alkenes in DMF with NaHCO₃ and 30% H₂O₂. In particular, Mn_29.39Fe_70.61-MOF-74 can achieve almost 100% conversion for styrene with 95.0% selectivity towards styrene oxide and be reused at least five times without loss of activity.