改性球形铁酸铋纳米材料的制备及光催化性能

Preparation and Photocatalytic Properties of Modified Spherical BiFeO3 Nanomaterials

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BiFeO_(3)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BiFeO_(3)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BiFeO_(3)纳米颗粒呈球状且具有较小的粒径,La的引入不仅影响了BiFeO_(3)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BiFeO_(3)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BiFeO_(3)催化效果提高了85.7%。相关机理研究结果表明La掺杂BiFeO_(3)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。

With the aggravation of water pollution,it is extremely important to explore efficient technologies to deal with water pollution.BiFeO_(3)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 BiFeO_(3)powder.Furthermore,Congo red and sewage were used as the target pollutant to explore the photocatalytic performance of La doped BiFeO_(3).The results show that La doped BiFeO_(3)nanoparticles are spherical and have small particle size.The introduction of La not only affects the magnetic properties of BiFeO_(3),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 BiFeO_(3)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 BiFeO_(3)at the same time.The results of related mechanism research indicate that the main active substance is hole when La doped BiFeO_(3)photocatalyst degrades Congo red.