【摘要】 随着水污染的加剧，研究环保高效的新型水污染处理技术尤为重要。采用溶胶-凝胶法制备了过渡金属离子La改性的BiFeO₃球形光催化材料，利用X射线衍射（X-ray diffraction, XRD）、扫描电子显微镜（scanning electron microscope, SEM）、傅里叶变换红外光谱仪（Fourier transform infrared spectrometer, FTIR）、紫外-可见分光光度法（ultraviolet-visible spectroscopy, UV-Vis）、振动样品磁强计（vibrating sample magnetometer, VSM）等表征手段对La掺杂的BiFeO₃粉末的结构、光学及磁性进行分析，并以刚果红和实际环境污水为目标污染物，探究其光催化性能。结果表明，La掺杂的BiFeO₃纳米颗粒呈球状且具有较小的粒径，La的引入不仅影响了BiFeO₃的磁性，还使其带隙由2.67 eV减小到2.02 eV。通过调控La的掺杂量，可有效提升BiFeO₃的光催化降解效率，当La掺杂量为5%时，可以将实际污染水体中的化学需氧量（chemical oxygen demand, COD）浓度降低40%。同时，在光催化60 min时可将浓度为20 mg/L的刚果红溶液完全降解，比同一时间BiFeO₃催化效果提高了85.7%。相关机理研究结果表明La掺杂BiFeO₃光催化剂降解刚果红时，起主要催化作用的活性物质是空穴。更多还原

【Abstract】 With the aggravation of water pollution, it is extremely important to explore efficient technologies to deal with water pollution. BiFeO₃ spherical photocatalytic material modified by transition metal ion La was prepared by sol-gel method. X-ray diffraction（XRD）, scanning electron microscope（SEM）, Fourier transform infrared spectrometer（FTIR）, ultraviolet-visible spectroscopy（UV-Vis） and vibrating sample magnetometer（VSM） were used to analyze the structure, optics and magnetism of La doped BiFeO₃ powder. Furthermore, Congo red and sewage were used as the target pollutant to explore the photocatalytic performance of La doped BiFeO₃. The results show that La doped BiFeO₃ nanoparticles are spherical and have small particle size. The introduction of La not only affects the magnetic properties of BiFeO₃, but also reduces its band gap from 2.67 eV to 2.02 eV. By regulating the doping amount of La, the photocatalytic degradation efficiency of BiFeO₃ can be effectively improved. When the doping amount of La is 5%, the chemical oxygen demand（COD） concentration in the actual polluted water can be reduced by 40%. Meanwhile, Congo red solution with a concentration of 20 mg/L can be completely degraded by photocatalysis for 60 min, which is 85.7% higher than that of BiFeO₃ at the same time. The results of related mechanism research indicate that the main active substance is hole when La doped BiFeO₃ photocatalyst degrades Congo red.更多还原