国家纳米科学中心唐智勇研究团队发现固定在金属有机框架化合物（MOF）节点上的铁氧簇（Fe-O cluster）可用于催化甲烷直接氧化。 该研究于2020年11月09日发表于国际一流学术期刊《德国应用化学》。

在这项工作中，课题组研究人员展示了具有可调谐电子态的MOF节点上的铁氧簇，可在50°C下将甲烷直接氧化成一碳有机含氧化合物。铁氧簇是嫁接在UiO-66（UiO代表奥斯陆大学）的无机Zr6节点上的，而UiO-66的有机对苯二甲酸（H2BDC）配体则被一元酸修饰如乙酸（AA）和三氟乙酸（TFA）部分取代。

实验和理论计算揭示，与UiO-66的Zr6节点配位的TFA基团由于具有吸电子能力，促进了邻近铁氧簇的氧化态，进而促进了甲烷的碳氢活化和选择性转化，导致相当高的一碳有机含氧化合物产率（4799 μmol gcat^-1 h^-1）和选择性（97.9%），比使用AA作为配体高出约8倍。

据悉，在温和条件下将甲烷高产率地直接氧化为高附加值有机氧化物仍然是一个巨大的挑战。

附：英文原文

Title: Fe‐O Clusters Anchored on Nodes of Metal‐Organic Frameworks for Direct Methane Oxidation

Author: Wenshi Zhao, Yanan Shi, Yuheng Jiang, Xiaofei Zhang, Chang Long, Pengfei An, Yanfei Zhu, Shengxian Shao, Zhuang Yan, Guodong Li, Zhiyong Tang

Issue&Volume: 09 November 2020

Abstract: Direct methane oxidation into value‐added organic oxygenates with high productivity under mild condition remains a great challenge. In this work, we show Fe‐O clusters on nodes of metal‐organic frameworks (MOFs) with tunable electronic state for direct methane oxidation into C1 organic oxygenates at 50°C. The Fe‐O clusters are grafted onto inorganic Zr6  nodes of UiO‐66 (UiO stands for University of Oslo), while the organic terephthalic acid (H2BDC) ligands of UiO‐66 are partially substituted with monocarboxylic modulators of acetic acid (AA) or trifluoroacetic acid (TFA). Experiments and theoretical calculation disclose that the TFA group coordinated with Zr6  node of UiO‐66 enhances the oxidation state of adjacent Fe‐O cluster due to its electron‐withdrawing ability, promotes the activation of C‐H bond of methane and increases its selective conversion, thus leading to the extraordinarily high C1 oxygenate yield of 4799 μmol gcat‐1 h‐1 with 97.9% selectivity, ~8 times higher than those modulated with AA.

DOI: 10.1002/anie.202013807

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202013807