K2Ti6O13 hybridized graphene oxide: Effective enhancement in photodegradation of RhB and photoreduction of U(VI)
K2Ti6O13 hybridized graphene oxide: Effective enhancement in photodegradation of RhB and photoreduction of U(VI)
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K2Ti6O13杂化氧化石墨烯：有效增强RhB的光降解和U(VI)的光还原
DOI：
10.1016/j.envpol.2019.02.025
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发表时间：
2019
影响因子：
8.9
通讯作者：
Hayat Tasawar
中科院分区：
文献类型：
--
作者：
Zhu Mingyu;Cai Yawen;Liu Shuya;Fang Ming;Tan Xiaoli;Liu Xiaoyan;Kong Mingguang;Xu Wei;Mei Huiyang;Hayat Tasawar
有机污染物和放射性核素对环境的污染已引起人们的高度关注。开发高效的消除方法成为迫切的需求。采用水热法制备了K2 Ti6 O 13（KTO）纳米带与氧化石墨烯（GO）纳米片（GO/KTO）的纳米复合材料，并将其用于RhB（染料）的光降解和U（VI）（放射性核素）的光还原。GO/KTO对RhB的吸附量和ln（C/C）-时间曲线的斜率（k）均高于GO和KTO。在不同的自由基清除剂存在下，超氧自由基（·O2−）被发现在反应中发挥最重要的作用。XPS实验表明，U（VI）被成功地光还原为毒性较小的U（IV）。对RhB和U（VI）的pH依赖性光催化实验均显示在中性pH值（从pH 6到pH 8）下的最佳性能。为了研究GO/KTO复合材料的光致发光增强的原因，对其形貌/微观结构、光学和光电化学性质进行了研究。GO/KTO的光电子和空穴分离能力以及GO/KTO的吸附能力的增强归因于KTO纳米带的结构位于GO纳米片的表面，这可以最大化KTO和GO之间的接触面积，从而大大减少与表面相关的氧缺陷，从而增强KTO和GO之间的电子界面转移，降低电子和空穴的复合效率。这些结果表明，GO/KTO在中性条件下处理有机污染物和高价重/放射性核素离子方面具有很大的应用潜力。
The environmental pollutions by organic pollutants and radionuclides have aroused great concern. Developing highly efficient elimination methods becomes an imperious demand. In this study, a nanocomposite of K2Ti6O13(KTO) nanobelts hybridized graphene oxide (GO) nanosheets (GO/KTO) was used to photodegrade RhB (dye) and photoreduce U(VI) (radionuclide), which was synthesized by a facile hydrothermal method. The adsorption capacity and the slope (k) of the curve -ln(C/C) versus time in photodegradation of RhB by GO/KTO were higher than that by GO and KTO. In the presence of different free radical scavengers, superoxide radical (·O2−) was found to play the most significant role in the reaction. The XPS experiment indicates U(VI) was successfully photoreduced to less toxic U(IV). The pH dependent photocatalytic experiments on RhB and U(VI) both showed the best performance at neutral pH value (from pH 6 to pH 8). To investigate the reason for the enhanced photocatalysis of GO/KTO, the morphology/microstructure, optical and photo-electrochemical properties were examined. The enhanced abilities of separation of photo electrons and holes and the adsorption of GO/KTO were ascribed to the structure of KTO nanobelts laying on the surface of GO nanosheets, which may maximize the contacting area between KTO and GO, and thus greatly reduce the surface related oxygen defects to enhance the electron interface transfer between KTO and GO and decrease the recombination efficiency of electrons and holes. These results showed the GO/KTO has great application potential in environmental treatment of organic pollutants and high valent heavy/radionuclide ions at neutral condition.