Enhanced Fenton-like catalytic activity and stability of g-C₃N₄ nanosheet-wrapped copper phosphide with strong anti-interference ability: Kinetics and mechanistic study

Metal-based Fenton-like catalysts usually activate H₂O₂ to produce free radicals (^•OH and O₂^•-) for the degradation of organic pollutants. However, a catalytic reaction dominated by free radicals is easily interfered with by various inorganic anions and water matrices. Herein, g-C₃N₄-wrapped copper phosphide (Cu_xP), as a highly efficient Fenton-like catalyst, was successfully synthesized by a simple low-temperature phosphidation method. The Cu_xP/g-C₃N₄ catalyst exhibited excellent catalytic ability for the removal of various organic contaminants over a wide pH range of 3-11. In addition, the catalyst exhibited strong anti-interference ability toward various inorganic anions (Cl^-, SO₄^2-, NO₃^-, F^-, H₂PO₄^-, HCO₃^- and CO₃^2-) and water matrices (lake water, river water, tap water and simulated water matrix). The reasons for this performance were analyzed by verifying the mechanism of the catalytic reaction. Compared to the pure Cu_xP catalyst, the Cu_xP/g-C₃N₄ composite possessed good catalytic stability. The enhanced and deactivated mechanisms of the Cu_xP/g-C₃N₄ catalyst were systematically analyzed by a series of characterization techniques. A possible reaction mechanism was also proposed based on the experimental results. This work provides new insights into designing highly efficient metal-based Fenton-like catalysts with strong anti-interference ability to practically treat wastewater.