Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru复合光催化剂的合成及其对磺胺甲噁唑药物废水降解性能研究

Preparation of Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru Composite Photocatalysts and Their Degradation Performances for Sulfamethoxazole

Bi_(x)O_(y)Br_(z)光催化剂在有机药物废水处理领域有着非常广阔的潜在应用价值,但光生电子-空穴对的快速复合限制了其应用。本文选用具有优良电子传递性能的Ti_(3)C_(2)作为助催化剂,首先利用Ti_(3)C_(2)表面丰富的Ti空位缺陷和高还原能力,制备了Ti_(3)C_(2)-Ru助催化剂,接着利用Ti_(3)C_(2)表面官能团与Bi^(3+)的离子键合力实现了Bi_(4)O_(5)Br_(2)在Ti_(3)C_(2)-Ru表面的原位生长,得到Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru复合光催化剂,从而实现了电子由Bi_(4)O_(5)Br_(2)到Ti_(3)C_(2)再到反应活性位点Ru的定向传递,最终使催化剂具有较高的光生载流子分离率和较低的界面电荷转移阻力,有效抑制了光生电子-空穴对的复合。同时以磺胺甲噁唑(SMX)为模拟药物污染物进行了光催化性能测试,结果表明所制备的Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru复合光催化剂展示出了优异的光催化降解SMX性能,在可见光下照射75 min,SMX的降解率达到95.1%,相较于纯的Bi_(4)O_(5)Br_(2)和Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)催化剂,其降解率分别提升了36.9个百分点和25.3个百分点。最后基于自由基捕获实验和催化剂能带结构分析提出了所制催化剂的降解机理。研究结果可为构建具有药物废水净化功能的光催化剂提供设计思路。

Bi_(x)O_(y)Br_(z)photocatalysts display great application potential in the field of organic pharmaceutical wastewater treatment,but the high recombination rate of photogenerated electron-hole pairs limits their application.In this work,Ti_(3)C_(2)with excellent electron transfer performance was selected as a cocatalyst.Firstly,Ti_(3)C_(2)-Ru cocatalyst was prepared by taking full use of abundant surface Ti vacancy defects and high reduction ability of Ti_(3)C_(2),then Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru composite photocatalysts were prepared by realizing in-situ growth of Bi_(4)O_(5)Br_(2) on Ti_(3)C_(2)-Ru surface through the ionic bonding force between Ti_(3)C_(2)surface functional groups and Bi^(3+).This special structure ensures the directional transfer of electrons from Bi_(4)O_(5)Br_(2)to Ti_(3)C_(2)and then to the reaction active site of Ru,thereby the composite catalysts exhibit higher photogenerated carrier separation rate and lower interfacial charge transfer resistance,which effectively inhibit the recombination rate of photogenerated electron-hole pairs.The photocatalytic performance of composite photocatalysts were evaluated by the sulfamethoxazole(SMX)degradation efficiency.The results reveal that the Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2)-Ru composite photocatalysts exhibit excellent photocatalytic performance on SMX degradation.The optimum removal efficiency of SMX reaches 95.1%under 75 min visible-light irradiation,which increase 36.9 percentage points of pure Bi_(4)O_(5)Br_(2)and 25.3 percentage points of Bi_(4)O_(5)Br_(2)/Ti_(3)C_(2),respectively.Finally,the underlying photocatalytic mechanism was elucidated based on the radical scavenging experiments and catalyst band structure.This results will provide a novel design idea for the construction of photocatalyst with pharmaceutical wastewater treatment capability.