Facile fabrication of magnetically separable graphitic carbon nitride photocatalysts with enhanced photocatalytic activity under visible light

Abstract

Because of their potential application in the conversion of solar energy to chemical energy, the development of semiconductor photocatalysts that have high reactivity under visible light has received great attention. In the present work, we illustrate the design and fabrication of magnetically separable polymeric carbon nitride photocatalysts, i.e. Fe₂O₃/g-C₃N₄ composite photocatalysts, a novel type of visible light driven photocatalyst with a cost-effective recovery manner. The obtained Fe₂O₃/g-C₃N₄ composite catalysts with different Fe₂O₃ contents were characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), vibration sample magnetometry (VSM) and thermogravimetric analysis (TGA). The saturation magnetization at 300 K varies from 0.37 to 1.56 emu g⁻¹, depending on the different Fe₂O₃ contents (2.8–11.6 wt%) in the Fe₂O₃/g-C₃N₄ composites, clearly indicating the excellent magnetic separation characteristics of the as-prepared photocatalysts. Remarkably, the photocatalytic activity of the magnetic Fe₂O₃/g-C₃N₄ photocatalysts under visible light irradiation was increased up to 1.8 times for the photodegradation of Rhodamine B (RhB) under visible light irradiation compared with the conventional pure g-C₃N₄ photocatalyst. A possible mechanism for the enhanced photocatalytic activity of the Fe₂O₃/g-C₃N₄ composite photocatalyst was also proposed to guide the further improvement of their photocatalytic activity.