BiOBr/protonated graphitic C3N4 heterojunctions: Intimate interfaces by electrostatic interaction and enhanced photocatalytic activity
BiOBr/protonated graphitic C3N4 heterojunctions: Intimate interfaces by electrostatic interaction and enhanced photocatalytic activity
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DOI：
10.1016/j.jallcom.2015.02.103
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发表时间：
2015-06
影响因子：
6.2
通讯作者：
Zhichong Yang;Jun Li;Fuxing Cheng;Zhi Chen;Xiaoping Dong
中科院分区：
文献类型：
--
作者：
Zhichong Yang;Jun Li;Fuxing Cheng;Zhi Chen;Xiaoping Dong
采用盐酸对石墨C3 N4进行质子化处理，提高了BiOBr/石墨C3 N4异质结光催化降解罗丹明B（RhB）的活性。质子化石墨C3 N4（pg-C3 N4）和BiOBr之间可能存在静电相互作用，在异质结中形成了紧密的界面，扫描电镜（SEM）和透射电镜（TEM）的结果表明了这一点。这种紧密耦合有利于pg-C3 N4与BiOBr之间的电荷转移，从而促进光生电子-空穴对的有效分离.研究了异质结组成对光催化活性的影响，当BiOBr/pg-C3 N4质量比为7：3时，光催化活性最高，分别是pg-C3 N4和BiOBr的35.03倍和33.72倍。自由基捕获实验证实了空穴和超氧自由基是RhB光降解过程中的主要反应物种。此外，还测试了BiOBr/pg-C3 N4异质结的稳定性，连续7次循环后，RhB降解效率仅下降9.6%。
In this work, enhanced photocatalytic activity of BiOBr/graphitic C3N4heterojunctions for degradation of Rhodamine B (RhB) were obtained by the protonation pretreatment of graphitic C3N4with hydrochloric acid. A possibly electrostatic interaction between protonated graphitic C3N4(pg-C3N4) and BiOBr provided a closely intimate interface in the heterojunction, which was demonstrated by the results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This tight coupling was favorable for the charge transfer between pg-C3N4and BiOBr, and therefore promoted the effective separation of photogenerated electron–hole pairs. The effect of composition in heterojunctions on photocatalytic activity was investigated, and the optimal photocatalyst with a BiOBr/pg-C3N4mass ratio of 7:3 showed a superior activity, which was 35.03 and 33.72 times higher than that over pg-C3N4and BiOBr, respectively. Radical trap experiments confirmed that the holes and superoxide radical species were the main reactive species in the RhB photodegradation process. Moreover, the stability of BiOBr/pg-C3N4heterojunction was also tested and the RhB degradation efficiency declined by only 9.6% after seven successive cycles.