摘要
电位相对较低的价带(VB)是限制体型聚酰亚胺(PI)光催化氧化能力的因素,PMDA/PDA线型聚酰亚胺具有相对较高的价带电位(+2.45 eV),表现出较强的氧化性,不需要构建异质结就能表现出较强的氧化降解能力。为了制备一种具有较高可见光催化活性的聚酰亚胺,以均苯四甲酸二酐(PMDA)和对苯二胺(PDA)为原料,乙醇为共溶剂,采用二步法制备具有共轭结构的线型聚酰亚胺(PI),采用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FTIR)、紫外可见漫反射仪(UV-vis DRS)、荧光光谱仪(PL)、X射线光电子能谱仪(XPS)等考察PI的化学组成、微观结构和光电化学性质,测定PI的禁带宽度、HOMO电位和最低未占据分子轨道(LUMO)电位。结果表明,线型PI的主要光催化活性中心是光生空穴,利用空穴的强氧化性降解罗丹明B(RhB)溶液,具有较高的光催化降解效果,降解效率是常用光催化剂g-C3N4的3倍。因此,PMDA/PDA线型聚酰亚胺具有较高的可见光催化活性及光催化稳定性。
The photocatalytic oxidation ability of polyimide is weak because of the relatively low valence band(VB).The valence band potential of the PMDA/PDA linear polyimide is+2.45 eV,showing that it has strong oxidizing property and strong oxidative degradation ability without constructing heterojunction.In order to prepare a kind of polyimide with high visible-light photocatalytic activity,linear polyimide(PI)with strong oxidizability is prepared by two-step method using pyromellitic dianhydride(PMDA)and p-phenylenediamine(PDA)as raw materials and ethanol as co-solvent.The chemical composition,microstructure and photoelectrochemical properties of PI are investigated by scanning electron microscopy(SEM),fourier infrared spectroscopy(FTIR),UV-vis diffuse reflectometer(UV-vis DRS),fluorescence spectrometer(PL)and X-ray photoelectron spectroscopy(XPS).The band gap width,Homo potential and lowest unoccupied molecular orbital(LUMO)potential of PI are measured.The results show that the main photocatalytic active center of the obtained polyimide is found to be photogenerated holes through a series of experiments.The photocatalytic activity of polyimide is evaluated by photodegradation of Rhodamine B,and the degradation efficiency of the as-prepared polyimide is three times as that of the commonly used photocatalyst g-C3N4.Therefore,PMDA/PDA linear polyimide is a kind of polyimide with high visible-light photocatalytic activity and high photocatalytic stability.
作者
张琪
朱学旺
罗青枝
殷蓉
王德松
ZHANG Qi;ZHU Xuewang;LUO Qingzhi;YIN Rong;WANG Desong(School of Material Science and Engineering,Hebei University of Science and Technology,Shijiazhuang,Hebei 050018,China;School of Science,Hebei University of Science and Technology,Shijiazhuang,Hebei 050018,China)
出处
《河北科技大学学报》
CAS
2019年第6期488-495,共8页
Journal of Hebei University of Science and Technology
基金
国家自然科学基金(21271061)
关键词
半导体材料
聚酰亚胺
均苯四甲酸二酐
对苯二胺
罗丹明B
光催化降解
semiconductor material
polyimide
pyromellitic dianhydride
phenylenediamine
Rhodamine B
photocatalytic degradation
