Singlet oxygen mediated iron-based Fenton-like catalysis under nanoconfinement
Singlet oxygen mediated iron-based Fenton-like catalysis under nanoconfinement
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DOI：
10.1073/pnas.1819382116
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发表时间：
2019-03
影响因子：
11.1
通讯作者：
Zhichao Yang;Jieshu Qian;A. Yu;B. Pan
中科院分区：
文献类型：
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作者：
Zhichao Yang;Jieshu Qian;A. Yu;B. Pan
意义 在本体相中，来自单电子转移的羟基自由基和来自O原子转移的高价铁氧物种竞争成为芬顿及相关反应中的反应中间体。然而，在纳米尺度的有限空间中，芬顿反应的行为是难以捉摸的。在此，我们报道了在内径~7 nm的碳纳米管内发生了前所未有的单线态氧介导的芬顿反应，显示出奇异的催化活性、不可预见的吸附依赖性选择性以及有机化合物氧化的pH稳定性。我们的结果表明芬顿反应的使用场景比以往探索的更多。几十年来，铁基类芬顿催化一直被认为是由羟基自由基或高价铁氧物种介导的，而只有零星的证据支持哈伯-韦斯循环中单线态氧（1O2）的生成。在此，我们报告了一种前所未有的单线态氧介导的类芬顿过程，该过程由分布在内径为～7 nm的多壁碳纳米管内的～2 nm Fe2O3纳米颗粒催化。与传统的类芬顿过程不同，这种精心设计的系统可以选择性地氧化可吸附的有机染料，氧化速率与吸附亲和力成线性比例。与非受限类似物相比，它对模型污染物亚甲基蓝也表现出显着更高的降解活性（快 22.5 倍）。引人注目的是，pH 值高达 9.0 时出人意料的稳定性极大地扩展了类芬顿催化剂在碱性条件下的使用范围。这项工作代表了纳米限制下类芬顿系统的设计和理解的根本性突破，可能会对其他领域，特别是生物系统产生影响。
Significance In the bulk phase, hydroxyl radical from the one-electron transfer and high-valent iron-oxo species from the O-atom transfer compete to be the reactive intermediates in the Fenton and related reactions. In the confined space at a nanoscale, however, the behavior of the Fenton reaction is elusive. Herein, we report an unprecedented singlet oxygen mediated Fenton’s reaction occurred inside carbon nanotube with inner diameter of ∼7 nm, showing exotic catalytic activities, unforeseen adsorption-dependent selectivity, and pH stability for the oxidation of organic compounds. Our results suggest the use of Fenton’s reaction in more scenarios than ever explored. For several decades, the iron-based Fenton-like catalysis has been believed to be mediated by hydroxyl radicals or high-valent iron-oxo species, while only sporadic evidence supported the generation of singlet oxygen (1O2) in the Haber–Weiss cycle. Herein, we report an unprecedented singlet oxygen mediated Fenton-like process catalyzed by ∼2-nm Fe2O3 nanoparticles distributed inside multiwalled carbon nanotubes with inner diameter of ∼7 nm. Unlike the traditional Fenton-like processes, this delicately designed system was shown to selectively oxidize the organic dyes that could be adsorbed with oxidation rates linearly proportional to the adsorption affinity. It also exhibited remarkably higher degradation activity (22.5 times faster) toward a model pollutant methylene blue than its nonconfined analog. Strikingly, the unforeseen stability at pH value up to 9.0 greatly expands the use of Fenton-like catalysts in alkaline conditions. This work represents a fundamental breakthrough toward the design and understanding of the Fenton-like system under nanoconfinement, might cause implications in other fields, especially in biological systems.