文摘
The multifunctional design of heterogeneous catalysts which can realize the selective oxidation of C–H bonds with oxygen at low temperature is of crucial importance in the catalysis community. Here, we report the designed synthesis of Cu-CuFe2O4@HKUST-1 heterostructures that is highly active for the selective oxidation of benzylic C–H bonds under mild conditions (60 °C). In the synthetic process, the Cu(0) component of Cu-CuFe2O4 nanoparticles gradually released Cu2+ ions which were in situ transformed into the HKUST-1 shell. The high activity can be attributed to a rationally multifunctional design of Cu-CuFe2O4@HKUST-1 heterostructures, in which Cu-CuFe2O4 can provide multiple active sites while HKUST-1 attracts and preconcentrates molecular oxygen. Notably, the catalytic performance under optimized reaction conditions (60 °C) was achieved in the oxidation of fluorene to fluorenone (conversion: > 99%, selectivity: > 99%). Furthermore, the Cu-CuFe2O4@HKUST-1 catalyst could be easily recovered by magnetic separation and reused for 10 times without significant loss of catalytic activity.
