Hierarchical FeWO<sub>4</sub> Microcrystals: Solvothermal Synthesis and Their Photocatalytic and Magnetic Properties

Highly hierarchical platelike FeWO<sub>4</sub> microcrystals have been synthesized by a simple solvothermal route using FeCl<sub>3</sub>·6H<sub>2</sub>O and Na<sub>2</sub>WO<sub>4</sub>·2H<sub>2</sub>O as precursors, where ethylene glycol (EG) plays an important role as a capping agent in directing growth and self-assembly of such unique structures. In addition, a certain amount of CH<sub>3</sub>COONa (NaAc) was necessary for the formation of such unique FeWO<sub>4</sub> microstructures. The photocatalytic property of as-synthesized hierarchical FeWO<sub>4</sub> microcrystals has been first studied, which shows excellent photocatalytic activity for the degradation of rhodamine B (RhB) under UV and visible light irradiation (modeling sunlight). Moreover, magnetic measurement indicates that hexangular FeWO<sub>4</sub> platelike microcrystals show a small ferromagnetic ordering at low temperature because of spin-canting of antiferromagnetic materials and surface spins of FeWO<sub>4</sub> nanoparticles.