Coordination and activation of nitrous oxide by iron zeolites
Coordination and activation of nitrous oxide by iron zeolites
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DOI：
10.1038/s41929-021-00602-4
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发表时间：
2021-04-01
期刊：
影响因子：
37.8
通讯作者：
Sels, Bert F.
中科院分区：
文献类型：
--
作者：
Bols, Max L.;Snyder, Benjamin E. R.;Sels, Bert F.
含铁沸石是一种多相催化剂，在惰性烃的选择性氧化和氧化亚氮（N2O）的催化分解中表现出显著的活性。N2O的还原对这两种功能都至关重要，但在N2O结合和活化过程中追踪铁活性位点的实验数据有限。本文分离了铁交换沸石β中n2o连接的Fe（ii）活性位点，并用变温穆斯堡尔光谱、漫反射紫外-可见-近红外光谱和傅里叶变换红外光谱对其进行了表征。在低温下，N2O通过末端氮原子与Fe（ii）中心形成大量的背键结合。在较高的温度下，Fe-N2O的相互作用减弱，有利于异构化成o键形式，这有利于o原子的转移。密度泛函理论计算表明了N2O结合和活化的几何和电子结构要求。沸石晶格所施加的几何畸变在活化N2O中起重要作用。这突出了铁分子筛催化剂结构控制功能的机制。含铁沸石可以有效地促进氧化亚氮介导的氧化反应，尽管关于氧化剂与金属中心相互作用的结构信息有限。在这里，作者报告了铁交换沸石β中n2o连接的Fe（ii）活性位点的表征。
Iron-containing zeolites are heterogeneous catalysts that exhibit remarkable activity in the selective oxidation of inert hydrocarbons and catalytic decomposition of nitrous oxide (N2O). The reduction of N2O is critical to both these functions, but experimental data tracking the iron active sites during N2O binding and activation are limited. Here, the N2O-ligated Fe(ii) active site in iron-exchanged zeolite beta is isolated and characterized by variable-temperature Mossbauer, diffuse reflectance UV-vis-NIR and Fourier transform infrared spectroscopy. N2O binds through the terminal nitrogen atom with substantial backbonding from the Fe(ii) centre at low temperature. At higher temperatures, the Fe-N2O interaction is weakened, facilitating isomerization to the O-bound form, which is competent in O-atom transfer. Density functional theory calculations show the geometric and electronic structure requirements for N2O binding and activation. A geometric distortion imposed by the zeolite lattice plays an important role in activating N2O. This highlights a mechanism for structural control over function in Fe-zeolite catalysts.Nitrous-oxide-mediated oxidation reactions can be effectively promoted by iron-containing zeolites, although structural information on the interaction between oxidant and metal centre is limited. Here, the authors report the characterization of the N2O-ligated Fe(ii) active site in iron-exchanged zeolite beta.