Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008, China.
Nanjing Institute of Geography and Limnology, State Key Laboratory of Lake Science and Environment, Chinese Academy of Sciences, Nanjing 210008, China.
J Hazard Mater. 2014 Feb 28;267:55-61. doi: 10.1016/j.jhazmat.2013.12.042. Epub 2013 Dec 30.
In this study, the roles of TaON and Ta3N5 in the degradation of atrazine by the visible-Fenton-like system were examined in detail. The TaON and Ta3N5 samples prepared by the nitridation of Ta2O5 and characterized by XRD, DRS, BET and PL analyses. The results showed that the TaON sample had weaker absorption in the visible region but higher specific surface area than the Ta3N5 sample. The degradation rate of atrazine in visible-TaON-Fenton-like system was 2.64 times than that in visible-Ta3N5-Fenton-like system. Both Fe(2+) and H2O2 could be reduced by eCB (electrons in the conduction band) in TaON or Ta3N5, while atrazine could not be oxidized by hVB (holes in the valance band). OH is the active species for the degradation of atrazine in visible-TaON/Ta3N5-Fenton-like systems. Majority of OH originated from Fenton reaction. After Fe(3+) was reduced by eCB to Fe(2+), Fe(2+) reacted quickly with H2O2 to generate OH. In addition, by capturing eCB, a little of H2O2 was reduced to yield OH, which contributed a small fraction of atrazine degradation. Based on the experimental results, the roles of TaON and Ta3N5 in the visible-Fenton-like system were proposed. And the higher photocatalytic activity of TaON than Ta3N5 was suggested to be due to the higher separation efficiency of electrons and holes, which may be related to the larger specific surface area.
在这项研究中，详细考察了 TaON 和 Ta3N5 在可见芬顿样系统中降解莠去津的作用。通过 Ta2O5 的氮化制备了 TaON 和 Ta3N5 样品，并通过 XRD、DRS、BET 和 PL 分析进行了表征。结果表明，TaON 样品在可见区的吸收较弱，但比 Ta3N5 样品具有更高的比表面积。在可见-TaON-芬顿样系统中，莠去津的降解速率是可见-Ta3N5-芬顿样系统的 2.64 倍。在 TaON 或 Ta3N5 中，电子在导带中（eCB）可以还原 Fe(2+)和 H2O2，而莠去津不能被价带中的空穴（hVB）氧化。OH 是可见-TaON/Ta3N5-芬顿样系统中降解莠去津的活性物质。大多数 OH 源自芬顿反应。Fe(3+)被 eCB 还原为 Fe(2+)后，Fe(2+)与 H2O2 迅速反应生成 OH。此外，通过捕获 eCB，少量的 H2O2 被还原生成 OH，这对莠去津的降解有一定贡献。根据实验结果，提出了 TaON 和 Ta3N5 在可见芬顿样系统中的作用。并且 TaON 比 Ta3N5 具有更高的光催化活性，这归因于电子和空穴的更高分离效率，这可能与更大的比表面积有关。
