Effect of a Magnetic Field on Photocatalytic Degradation of Rhodamine B Over g-C3N4

Abstract

Magnetic fields have potential applications in photocatalysis. However, there is limited research on the effect of magnetic fields on heterogeneous photocatalysis, and the action mechanism remains unclear. In this study, the photocatalytic degradation of rhodamine B over g-C3N4 in an aqueous solution was investigated, and the adsorption and photocatalytic activity were analyzed in the absence and presence of a magnetic field. Furthermore, the infrared absorption frequency of the bending vibration of water was measured in real-time. The results show that the adsorption and photocatalytic efficiencies were positively correlated with the magnetic field intensity in the range of 0∼2 T, while high-intensity magnetic fields (4∼8 T) played an inhibitory role. In addition, the infrared absorption frequencies of water exhibited a red-shift under 1 T and 2 T magnetic fields at 37 °C, while the absorption frequencies under 4 T and 8 T magnetic fields were the same as that in the absence of magnetic fields. The effects of the magnetic field on the g-C3N4 photocatalytic efficiency and water infrared absorption frequency were similar, suggesting that the effect of the magnetic field on the water structure may be one factor affecting the g-C3N4 photocatalytic efficiency.