粒径可控的纳米铁酸铋的制备及其光催化性能

Preparation and Photocatalytic Performance of Nano-bismuth Ferrite with Tunable Size

采用改进的聚丙烯酰胺凝胶法制备了BiFeO3纳米颗粒,利用热重-差热、红外光谱及X射线衍射等手段研究了干凝胶的热分解及BiFeO3的成相过程.结果表明,在600°C煅烧可制备出高纯的BiFeO3纳米颗粒.同时发现,随着双丙烯酰胺含量的增加,所得样品晶粒尺寸逐渐减小,从而制备出平均粒径约52～110nm的系列BiFeO3颗粒,颗粒尺寸分布均匀,形貌规整,近似呈球形.以甲基橙为目标降解物,研究了BiFeO3纳米颗粒的光催化性能.结果表明,在紫外光和可见光辐照下该纳米颗粒均表现出良好的光催化活性,且随着颗粒尺寸减小,催化活性增加.适宜的甲基橙初始浓度为10mg/L,催化剂用量约为2.5g/L.

A modified polyacrylamide gel method was used to fabricate BiFeO3 nanoparticles.Thermogravimetric analysis,differential scanning calorimetry,Fourier transform infrared spectroscopy,and X-ray diffraction were used to investigate the thermal decomposition process of xerogel and the formation of BiFeO3 phase.It is demonstrated that high phase purity BiFeO3 nanoparticles can be prepared at a calcination temperature of 600 °C.Bisacrylamide,which acts as a crosslinking agent,plays an important role in tailoring the grain size of the resulting BiFeO3 nanoparticles.With increasing bisacrylamide content,the grain size decreases gradually.As a result,a series of BiFeO3 samples with average grain size of 52-110 nm were prepared.Scanning electron microscopy reveals that the prepared BiFeO3 nanoparticles are regularly spherical in shape with uniform particle size distribution.The photocatalytic activity of BiFeO3 nanoparticles was investigated by the degradation of methyl orange （MO）.The experimental results reveal that they exhibit a pronounced photocatalytic activity for the MO decomposition under ultraviolet and visible-light irradiation.With decrease in particle size,the reactive activity increases.The optimum conditions for the photocatalytic decolorization were determined to be initial MO concentration of ～10mg/L and catalyst amount of ～2.5g/L.