FeII/FeIII Doped Bi/BiOBr Hierarchical Microspheres as a Highly Efficient Catalyst for Degradation of Organic Contaminants at Neutral pH: The Role of Visible Light and H2O2

A novel Fe-II/Fe-III doped Bi/BiOBr (FBB) visible-light, Fenton-like catalyst was successfully synthesized by using the solvothermal method. The morphological and structural features of FBB were analyzed by XRD, field emission (FE)-SEM, TEM, Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS) techniques. The results revealed that the presence of Fe could promote the growth of Bi metal nanoparticles, and increase the specific surface areas of FBB. RhodamineB (RhB) photodegradation experiments indicated that FBB with the Fe/Bi molar ratio (0.2-0.3) exhibited higher photocatalytic activities. In the photo-Fenton-like reaction, the degradation efficiency of bisphenolA (BPA) over FBB-25 was increased to 100% within 30min whereas it was 3% and 12% in the Fenton-like and photocatalytic reactions. Moreover, 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), and 2,4,6-trichlorophenol (2,4,6-TCP) were completely degraded within 30min over FBB-25. The presence of visible light can promote the rapid reaction rate between Fe-II and Fe-III over FBB with H2O2, producing more hydroxyl radicals ((OH)-O-center dot) and more holes. The radical scavenger experiments demonstrated that holes and hydroxyl radicals ((OH)-O-center dot) were the main active species. FBB-25 is still stable after fivecycles. Therefore, FBB-25 has great potential in wastewater treatment.