Iron-containing heterogeneous catalysts hold great promising for the direct hydroxylation of benzene to phenol. However, their catalytic performance is greatly hampered by the inherent drawbacks of iron-containing solids, in particular their hydrophilic surface structure and inevitable leaching of iron species during the Fenton process, which result in poor selectivity and durability toward phenol production. Herein, we demonstrate that the encapsulation of iron nanoparticles with N-doped carbon layer as core–shell nanostructures (Fe@NC) is a promising synthetic strategy to advance iron-containing solids for benzene hydroxylation. The rigid carbon shells conformably coating on iron cores not only protect iron from leaching but also facilitate the selective adsorption of benzene molecules on Fe@NC because of their excellent stability against acid etching and hydrophobic surface with the unique π-conjugated electron system. As a result, Fe@NC exhibit a robust catalytic durability and good yield with high selectivity for the direct hydroxylation of benzene to phenol. Benefiting from their unique core–shell nanostructures and strong host–guest electron interaction between metals and carbons, Fe@NC are expected to be promising also for other liquid-phase organic synthesis.

中文翻译：

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N掺杂碳壳中包裹的Fe纳米粒子上苯选择性地羟基化为苯酚

含铁的多相催化剂对于将苯直接羟基化为苯酚具有广阔的前景。然而，它们的催化性能被含铁固体的固有缺点极大地阻碍，特别是它们的亲水性表面结构以及在芬顿过程中不可避免地铁种类的浸出，这导致差的选择性和对苯酚生产的耐久性。在本文中，我们证明以N掺杂碳层作为核壳纳米结构（Fe @ NC）封装铁纳米粒子是一种有前途的合成策略，可以提高含铁固体用于苯羟基化。在铁芯上顺应性地覆盖有刚性碳壳，不仅保护铁免于浸出，而且由于苯胺分子具有独特的π共轭电子体系，因此对酸蚀和疏水表面具有出色的稳定性，因此可以促进Fe @ NC上苯分子的选择性吸附。结果，Fe @ NC对苯直接羟基化为苯酚显示出强大的催化耐久性和良好的产率以及高选择性。受益于它们独特的核-壳纳米结构以及金属和碳之间强的主体-客体电子相互作用，Fe @ NC也有望在其他液相有机合成中大有前途。Fe @ NC对苯直接羟基化为苯酚具有强大的催化耐久性和良好的产率，并具有很高的选择性。受益于它们独特的核-壳纳米结构以及金属和碳之间强的主体-客体电子相互作用，Fe @ NC也有望在其他液相有机合成中大有前途。Fe @ NC对苯直接羟基化为苯酚具有强大的催化耐久性和良好的产率，并具有很高的选择性。受益于它们独特的核-壳纳米结构以及金属和碳之间强的主体-客体电子相互作用，Fe @ NC也有望在其他液相有机合成中大有前途。