Synthesis of single-crystal dendritic iron hydroxyl phosphate as a Fenton catalyst

Abstract

In this work, the single-crystal dendritic iron hydroxyl phosphate is synthesized via a facile and well-controlled hydrothermal process without any additional surfactant or template. The morphology of the product at various scales is characterized by scanning electron microscopy and transmission electron microscopy. The phase and crystal structure is determined and carefully confirmed by using X-ray powder diffraction, high resolution transmission electron microscopy and selected area electron diffraction combined with thermal analysis comprehensively. A reasonable self-template route, as well as the precipitation–dissolution–recrystallization process is revealed according to the time dependence of morphology, crystal structure, zeta potential and precipitate amount. Finally, the single-crystal dendrite is tested as a Fenton catalyst for the degradation of phenol, a typical advanced oxidation process (AOP). Attributed to the perfect crystal structure and the hierarchical architecture, this novel catalyst presents numerous advantages including remarkable catalytic activity over a wide pH range (e.g., pH = 3–8), outstanding cycle performance (no observation of activity loss in five runs), and extremely low leaching iron concentration (below 0.5 mg L⁻¹).