Eu^(3+)掺杂γ-Bi_2MoO_6的合成及其光催化活性研究

Synthesis of Eu^(3+) Doped γ-Bi_2MoO_6 and Study on Its Photocatalytic Activity

以钼酸铵、硝酸铋和硝酸铕为原料,采用简单水热技术成功获得了Eu^(3+)掺杂的片状钼酸铋(γ-Bi_2MoO_6)光催化剂,借助X-射线衍射(XRD)、扫描电镜(SEM)、紫外-可见吸收光谱(UV-Vis)等测试手段对样品的物相组成、形貌和光吸收等进行了表征,并以刚果红和2,4-二硝基苯酚为模型污染物,考察了Eu^(3+)掺杂对Bi_2MoO_6光催化性能的影响。结果表明,利用这种简单的水热合成方法获得层状结构的Bi_2MoO_6,Eu^(3+)掺杂对Bi_2MoO_6光催化活性的影响与其掺杂量有关,当Eu^(3+)掺杂量为0.75%(原子分数)时,催化剂活性最好。金卤灯光照70 min,0.75%(原子分数)Eu^(3+)/Bi_2MoO_6对2,4-二硝基苯酚降解率为54.2%,而相同条件下的纯Bi_2MoO_6对2,4-二硝基苯酚降解率仅为8.1%。根据活性数据,文中Eu^(3+)掺杂Bi_2MoO_6的活性增强机理进行了讨论,认为Eu^(3+)掺杂影响了Bi_2MoO_6的吸附性能、光吸收特性及光生载流子的分离效率,进而对Bi_2MoO_6的光催化活性产生显著影响。

Using bismuth nitrate,ammonium molybdate and europium nitrate as raw materials,flake- like Eu3＋doped bismuth molybdate（ γ- Bi_2MoO_6 ） has been successfully synthesized via a facile hydrothermal process. XRD,SEM and UV- Vis DRS Spectrum techniques were employed to characterize the phase composition,morphology and spectrum properties of the as- synthesized samples. Congo Red and 2,4- dinitrophenol were selected as a model pollutant to investigate the photocatalytic activity of as synthesized sample. Furthermore,the effect of Eu3＋doping amount on the γ- Bi_2MoO_6 photocatalytic activity was also investigated. The experimental results indicated that Eu3＋doping can enhance the photocatalytic activity ofγ- Bi_2MoO_6 for the photodegradation of Congo Red and 2,4- dinitrophenol,and the amount of Eu3＋doping has a serious effect on the photocatalytic activity of γ- Bi_2MoO_6 photocatalyst. The optimum doping amount of Eu3＋is 0. 75at%. Under the metal halide lamp light irradiation for 70 min,the photodegradation rate of 2,4- dinitrophenol reaches to 54. 2% using0. 75at% Eu3＋/ γ- Bi_2MoO_6 as photocatalyst,which is much higher than that of pure γ- Bi_2MoO_6 ＋（ 8. 1%）. Based on the experimental results,the mechanism for the enhancement photocatalytic activity of Eu3＋doped γ- Bi_2MoO_6 was also discussed. In Eu3＋doped γ- Bi_2MoO_6 system,the enhanced photocatalytic activity was ascribed to photoelectron transfer from conduction band of γ- Bi_2MoO_6 to the doping energy level of Eu3＋,resulting in the enhancement of separation efficiency of photoinduced carrier and enhancement of absorption property for pollutants.