N掺杂石墨炔/Bi_(2)GeO_(5)复合材料的合成及光催化性能

Synthesis and Photocatalytic Properties of N-Graphyne/Bi_(2)GeO_(5)Composites

以N掺杂石墨炔、硝酸铋和二氧化锗为原料,在180℃的水和二乙醇胺混合溶剂中保温18 h,原位合成了N掺杂石墨炔/锗酸铋(N-GY_(x)/Bi_(2)GeO_(5))复合材料。采用X射线衍射仪、扫描电子显微镜、X射线光电子能谱仪、紫外-可见分光光度计、光致发光光谱仪等多种表征技术对样品的晶相、形貌、元素组成和光学性能进行了分析。光催化测试表明,60 min光照下,N-GY_(3)/Bi_(2)GeO_(5)光催化降解亚甲基蓝的效率为82.93%,约是Bi_(2)GeO_(5)(64.52%)的1.29倍。三次循环光催化实验后,复合材料的光催化活性保持86.08%,晶相组成也没有明显的变化,表明样品具有较好的光催化稳定性。活性物种捕获实验证实h+在光催化降解亚甲基蓝的过程中起主要作用。由(光)电化学测试可知,与Bi_(2)GeO_(5)相比,N-GY_(3)/Bi_(2)GeO_(5)具有较大的光电流、较小的界面电荷转移电阻和更负的平带电位。氮掺杂石墨炔的引入,提高了Bi_(2)GeO_(5)的光吸收能力和光生载流子的分离效率,从而增强了光催化降解亚甲基蓝的效率。

N-graphyne/Bi_(2)GeO_(5)(N-GY_(x)/Bi_(2)GeO_(5))composites were synthesized in situ using Ndoped graphyne,bismuth nitrate and germanium dioxide as raw materials in a mixed solvent of water and diethanolamine by keeping at 180℃for 18 h.The crystal phases,morphologies,elemental compositions and optical properties of the samples were analyzed by multiple characterization technologies including X-ray diffractometer,scanning electron microscope,X-ray photoelectron spectroscope,ultraviolet visible spectrophotometer,photoluminescence spectrometer,etc.The photocatalytic tests show that after illumination for 60 min,the photocatalytic degradation efficiency of methylene blue by N-GY_(3)/Bi_(2)GeO_(5)is 82.93%,which is about 1.29 times that of Bi_(2)GeO_(5)(64.52%).After three-cycle photocatalytic tests,the photocatalytic activity of composites maintains 86.08%and crystal phase compositions do not obviously change,indicating that the samples have good photocatalytic stabilities.The active species capture experiments confirm that h+plays a main role in photocatalytic degradation of methylene blue.The optical and electrochemical tests show that compared with Bi_(2)GeO_(5),NGY_(3)/Bi_(2)GeO_(5)have larger photocurrent,smaller interfacial charge transfer resistance and more negative flat band potential.The introduction of N-graphyne improves light absorption capacity and separation efficiency of photogenerated carriers of Bi_(2)GeO_(5),thus enhancing photocatalytic degradation efficiency of methylene blue.