Low-crystalline Ce-based bimetallic MOFs synthesized via DBD plasma for excellent visible photocatalytic performance

A series of low-crystalline bimetallic Fe/Ce-MOFs were synthesized via dielectric barrier discharge (DBD) plasma for the first time. The incorporation of Fe greatly changed the coordinate structure of Ce-MOFs, inducing low crystallinity. Low-crystalline Fe/Ce-MOFs exhibited rich active sites and abundant oxygen defects. The oxygen defects could concentrate photogenerated electrons, and promote photogenerated electron-hole separation. Fe/Ce-MOFs-2 (Fe:Ce=1:2) had relatively narrow band gap and low recombination rate of photogenerated electron-hole, which exhibited excellent photocatalytic activity with degradation rate of 93% for methyl orange (MO, 20 mg/L) within 30 min under visible light. The electron paramagnetic resonance (EPR) measurements indicated that hydroxyl radicals (·OH) and superoxide radicals (·O2–) were the most active species during photocatalytic process. This efficient, facile and economical strategy might be advantageous to prepare other low-crystalline bimetallic MOFs with excellent performance.