Elucidation and Evolution of the Active Component within Cu/Fe/ZSM-5 for Catalytic Methane Oxidation: From Synthesis to Catalysis
Elucidation and Evolution of the Active Component within Cu/Fe/ZSM-5 for Catalytic Methane Oxidation: From Synthesis to Catalysis
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DOI：
10.1021/cs3007999
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发表时间：
2013-04-01
期刊：
影响因子：
12.9
通讯作者：
Hutchings, Graham J.
中科院分区：
文献类型：
--
作者：
Hammond, Ceri;Dimitratos, Nikolaos;Hutchings, Graham J.
甲烷氧化为甲醇的一步催化路线的开发仍然是催化领域的最大挑战之一。特别重要的是需要开发在温和反应条件下进行的有效路线，以避免目前实践的合成气路线的更深氧化和经济限制。最近，已证明含铜和铁的沸石是用于这种一步法的有效催化剂。所讨论的催化剂（Cu-Fe-ZSM-5）能够在水介质中以过氧化氢作为末端氧化剂选择性地将甲烷转化为甲醇。然而，尽管其具有高活性和无与伦比的甲醇选择性，但其活性的来源及其活性物质的确切性质尚未完全了解。通过结合催化和光谱研究，我们在此证明，框架外的Fe物种是甲烷氧化催化剂的活性组分，虽然这些网站的物种从合成到催化显着改变所观察到的活性和选择性。还考虑了该系统与其他含铁沸石催化过程（例如N2 O介导的苯羟基化）之间的相似性和差异。
The development of a catalytic, one-step route for the oxidation of methane to methanol remains one of the greatest challenges within catalysis. Of particular importance is the need to develop an efficient route that proceeds under mild reaction conditions so as to avoid deeper oxidation and the economic limitations of the currently practiced syngas route. Recently, it was demonstrated that a copper- and iron-containing zeolite is an efficient catalyst for such a one-step process. The catalyst in question (Cu-Fe-ZSM-5) is capable of selectively transforming methane to methanol in an aqueous medium with hydrogen peroxide as the terminal oxidant. Nevertheless, despite its high activity and unparalleled methanol selectivity, the origin of its activity and the precise nature of its active species are not yet fully understood. Through a combination of catalytic and spectroscopic studies, we hereby demonstrate that extraframework Fe species are the active component of the catalyst for methane oxidation, although the speciation of these sites from synthesis to catalysis significantly alters the observed activity and selectivity. The analogies and differences between this system and other iron-containing zeolite-catalyzed processes, such as N2O-mediated benzene hydroxylation, are also considered.