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.