Low content Ni-doped BiFeO3 with efficient photo-Fenton degradation of tetracycline

Abstract

In the present study, Ni-doped BiFeO3 (BiFe1-xNixO3, marked as BFNO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) visible light photocatalytic materials were prepared by sol-gel method. It is found that Ni doping could make the BiFeO3 absorption band red-shifted, enhance the absorption of visible light and reduce the bandgap. The photogenerated electron-hole complex of the material was effectively suppressed after Ni doping. Meanwhile, the magnetic measurements indicated that Ni doping could significantly enhance the saturation magnetization of BiFeO3, and the saturation magnetization of the materials increased exponentially with the increase of Ni doping. The photo-Fenton degradation performance of BFNO on tetracycline (TC) was investigated under visible light exposure. It was found that BFNO-8 (BiFe1-xNixO3, x = 0.08) was an effective catalyst for the degradation of TC, and the addition of 4 mmol/L H2O2 and 0.7 g/L of BFNO-8 could improve the degradation rate of TC to 96% within 120 min. The photocatalytic performance of BFNO-8 was so stable that it maintained a high degradation rate of TC even after 4 reuse times. Based on the radical capture experiments and electron paramagnetic resonance (EPR) results, the possible reaction mechanism of TC degradation by BFNO-8 was speculated to be that photocatalysis accelerated the Fe2+/Fe3+ recycling, formed the electron capture center, and accelerated the effective decomposition of H2O2.