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Mechanistic Investigations of the Pyridinic N–Co Structures in Co Embedded N-Doped Carbon Nanotubes for Catalytic Ozonation
ACS ES&T Engineering Pub Date : 2020-10-01 , DOI: 10.1021/acsestengg.0c00004
Yuxian Wang 1 , Nuo Ren 1 , Jiaxin Xi 1 , Ya Liu 1 , Tao Kong 1 , Chunmao Chen 1 , Yongbing Xie 2 , Xiaoguang Duan 3 , Shaobin Wang 3
Affiliation  

High-performance and robust catalysts act as core drivers for advanced oxidation technologies for decontamination of water resources. In this study, we used a facile strategy to prepare magnetic and N-doped carbon nanotubes with cobalt encapsulation (Co–N@CNTs) to catalyze ozone for decomposition of aqueous organic pollutants. By regulating the thermal conditions during the synthesis, the derived Co–N@CNTs manifested maneuvered adsorption capabilities. The embedded Co nanoparticles (NPs) not only afforded carbon nanotubes with a magnetic property but also significantly boosted catalytic ozonation due to the synergistic coupling of the Co interface and N-doped graphitic layer. Formation of such a coordinating structure accelerated electron transfer at the interface and increased the conductivity of surface carbon to coordinate a redox reaction. Density functional theory (DFT) calculations and experimental evidence confirmed that cobalt coupled with graphene with pyridinic N dopants was the most favorable structure, which remarkably enhanced ozone adsorption and its dissociation to generate reactive oxygen species (ROS). Intriguingly, the catalytic ozonation underwent different nonradical regimes dependent on the molecular structures of target organics. In terms of ROS, surface-adsorbed atomic oxygen (*Oad) was responsible for degradation of oxalic acid, while phenolics were primarily degraded by O3 molecules and singlet oxygen (1O2). This study provides a cost-efficient and recyclable carbocatalyst for wastewater decontamination and new insights into the structure–functional relationships in carbon-based advanced oxidation processes.

中文翻译:

Co嵌入N掺杂碳纳米管中用于催化臭氧化的吡啶N-Co结构的机理研究

高性能和坚固的催化剂是用于水资源净化的先进氧化技术的核心驱动力。在这项研究中,我们采用了一种简便的策略来制备磁性和N掺杂的碳纳米管,并进行钴包封(Co–N @ CNTs),以催化臭氧分解有机有机污染物。通过调节合成过程中的热条件,得到的Co-N @ CNT表现出可操纵的吸附能力。嵌入的Co纳米颗粒(NPs)不仅为碳纳米管提供了磁性,而且由于Co界面和N掺杂石墨层的协同偶联,大大促进了催化臭氧化作用。这样的配位结构的形成加速了界面处的电子转移并增加了表面碳的电导率以配位氧化还原反应。密度泛函理论(DFT)的计算和实验证据证实,钴和石墨烯与吡啶N掺杂剂偶联是最有利的结构,它显着增强了臭氧的吸附及其解离作用,从而生成活性氧(ROS)。有趣的是,取决于目标有机物的分子结构,催化臭氧化反应经历了不同的非自由基机制。就ROS而言,表面吸附的原子氧(* O 取决于目标有机物的分子结构,催化臭氧化反应经历了不同的非自由基反应。就ROS而言,表面吸附的原子氧(* O 取决于目标有机物的分子结构,催化臭氧化反应经历了不同的非自由基反应。就ROS而言,表面吸附的原子氧(* Oad)负责草酸的降解,而酚类化合物主要被O 3分子和单线态氧(1 O 2)降解。这项研究为废水净化提供了一种具有成本效益的可循环使用的碳催化剂,并对基于碳的高级氧化工艺中的结构-功能关系提供了新的见解。
更新日期:2020-10-01
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