Sn^(4+)离子掺杂ZnO纳米材料的制备及其光催化性能研究

Research on preparation and photocatalytic activity of Sn^(4+)-doped ZnO

采用醇热法,成功制备了锡离子(Sn^(4+))掺杂摩尔分数分别为1%、3%、5%的氧化锌(ZnO)光催化剂,利用XRD、SEM、TEM、EDS和UV-vis DRS等测试手段探究了Sn^(4+)掺杂量对所得ZnO纳米粒子的结构、形貌及光学性能的影响。结果表明,Sn^(4+)的掺杂并未影响ZnO的晶型和形貌,但是随着掺杂量的增加,ZnO晶粒的尺寸逐渐减小,禁带宽度也相应减小。以对甲基橙(MO)溶液的脱色降解为反应模型,光降解实验结果表明:Sn^(4+)掺杂提高了ZnO纳米粒子的光催化活性,当Sn^(4+)掺杂量为5%时光降解性能最优,降解速率为0.01778 min^(-1),是纯相ZnO的1.83倍。这可能是因为Sn^(4+)掺杂导致ZnO晶粒尺寸的减小,比表面积增大;此外,杂质能级的引入降低了光激发所需能量,促进了光生电子-空穴对的有效分离。

A series of Sn^(4+)-doped ZnO samples with various doping concentration(mole ratio 1%,3%,5%)were prepared by alcohol-thermal method.XRD,SEM,TEM,EDS and UV-vis DRS were used to investigated the crystal structure,morphology,element composition and optical properties of the prepared samples.The effects of the Sn^(4+)-doped amount on the photocatalytic activity of ZnO were also discussed.The results showed that Sn^(4+)doping did not affect the morphology of ZnO,but the size of the ZnO grain decreased with the increment of Sn^(4+)amount and the band gap of ZnO decreased.Methyl orange was used as a probe molecule to evaluate the photocatalytic activity of pure ZnO and Sn^(4+)-doped ZnO.The resulted showed that 5%Sn^(4+)-ZnO sample showed the highest photocatalytic performance,the degradation rate of ZnO on MO was 1.83 times as great as that of pure ZnO.The enhanced photocatalytic activity of Sn^(4+)-doped ZnO was probably due to the decrease of the grain size of ZnO and the increase of specific surface area.Besides,the introduced impurity energy level reduced the excitation energy and promoted the effective separation of photoinduced electron-hole pairs.