Cu(II) doped FeOCl as an efficient photo-Fenton catalyst for phenol degradation at mild pH

In this work, the Cu(II) doped iron oxychloride composites (Cu-FeOCl) were successfully synthesized and applied to the photo-Fenton degradation of phenol for the first time. Effect of various objective parameters on catalytic performance have been systematically evaluated, such as the doping amount of Cu(II), catalyst dose, pH value and H2O2 dose. The Cu(II) doping in FeOCl accelerated significantly the decomposition of H2O2 to generate hydroxyl radicals (•OH). Furthermore, the introduction of Cu(II) would produce lattice defects on the surface of FeOCl, which was benefit for the separation efficiency of the photogenerated electron-hole pairs. The 0.5Cu-FeOCl composite exhibited excellent degradation performance over a wide pH range of 3–8. The 0.5Cu-FeOCl/H2O2/Vis system degraded 95.2% of phenol (20 mg/L) within 14 min and removed 79.9% TOC within 120 min with low dosage of H2O2 (3 mM). The main intermediates of phenol degradation were identified by LC-MS, and a possible photo-Fenton catalytic mechanism for phenol degradation by 0.5Cu-FeOCl catalyst was proposed. This study would provide some new insights into developing photo-Fenton catalysts and treatment of phenolic organic wastewater.