Nitrogen-doped carbon nanotubes enhanced Fenton chemistry: Role of near-free iron(III) for sustainable iron(III)/iron(II) cycles.
Nitrogen-doped carbon nanotubes enhanced Fenton chemistry: Role of near-free iron(III) for sustainable iron(III)/iron(II) cycles.
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DOI：
10.1016/j.watres.2021.117984
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发表时间：
2021-12
期刊：
影响因子：
12.8
通讯作者：
Chenying Zhou;Peng Zhou;Minglu Sun;Yang Liu;Heng Zhang;Z. Xiong;J. Liang;Xiaoguang Duan;B. Lai
中科院分区：
文献类型：
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作者：
Chenying Zhou;Peng Zhou;Minglu Sun;Yang Liu;Heng Zhang;Z. Xiong;J. Liang;Xiaoguang Duan;B. Lai
Fe（II）回收的缓慢动力学严重阻碍了芬顿反应（Fe（II）/H2 O2）向实际应用的科学进展。在这里，我们提出了一种新的机制，即无金属氮掺杂碳纳米管（NCNT）可以提高芬顿化学与H2 O2作为电子供体的Fe（III）的氧化电位。在NCNT/Fe（III）/H2 O2体系中，NCNT能显著促进Fe（III）/Fe（II）循环产生羟基自由基（·OH），并具有良好的稳定性，可多次循环使用（10次以上）。尽管NCNT上的羰基可以充当Fe（III）还原的电子供应者，但NCNT的行为与常见的还原剂（例如羟胺和硼）不同。电化学分析和密度泛函理论计算揭示了NCNT的氮位可以与Fe（III）弱结合，以提高Fe（III）（称为近游离Fe（III），主要是FeOH 2+）在pH 2.0至4.0范围内的氧化电位。在没有外界刺激或电子传递剂的情况下，近游离态Fe（III）可以促进H2 O2诱导的Fe（III）还原，从而引发芬顿链式反应，产生持久的·OH.令我们高兴的是，这是N掺杂碳材料的共同性质（例如，石墨烯、碳纳米纤维和乙炔黑），因此我们的研究为促进芬顿化学提供了一种新颖的、可持续的和绿色的策略。
The sluggish kinetics of Fe(II) recovery strongly impedes the scientific progress of Fenton reaction (Fe(II)/H2O2) towards practical application. Here, we propose a novel mechanism that metal-free nitrogen-doped carbon nanotubes (NCNT) can enhance Fenton chemistry with H2O2as electron donors by elevating the oxidation potential of Fe(III). NCNT remarkably promotes the circulation of Fe(III)/Fe(II) to produce hydroxyl radical (•OH) with excellent stability for multiple usages (more than 10 cycles) in the NCNT/Fe(III)/H2O2system. Although carbonyl on NCNT can act as the electron supplier for Fe(III) reduction, the behavior of NCNT is distinct from common reductants such as hydroxylamine and boron. Electrochemical analysis and density functional theory calculation unveil that nitrogen sites of NCNT can weakly bind with Fe(III) to elevate the oxidation potential of Fe(III) (named near-free Fe(III), primarily FeOH2+) at pH ranging from 2.0 to 4.0. Without inputs of external stimulations or electron sacrificers, near-free Fe(III) can promote H2O2induced reduction of Fe(III) to initiate Fenton chain reactions for long-lasting generation of•OH. To our delight, it is a common property of N-doped carbon materials (e.g., graphene, carbon nanofibers, and acetylene black), our research thus provides a novel, sustainable, and green strategy for promoting Fenton chemistry.