文献精选-20160312-分子筛篇
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1. 吉林大学于吉红老师刚发的Science
一句话描述：通过UV和Fenton两种方式引入•OH自由基加速了分子筛的结晶；用EPR结合DFT计算说明了•OH自由基促进结晶的具体作用方式（主要影响成核）。
In the hydrothermal crystallization of zeolites from basic media, hydroxide ions (OH–) catalyze the depolymerization of the aluminosilicate gel by breaking the Si, Al–O–Si, Al bonds and catalyze the polymerization of the aluminosilicate anions around the hydrated cation species by remaking the Si, Al–O–Si,Al bonds. We report that hydroxyl free radicals (•OH) are involved in the zeolite crystallization under hydrothermal conditions. The crystallization processes of zeolites—such as Na–A, Na–X, NaZ–21, and silicalite-1—can be accelerated with hydroxyl free radicals generated by ultraviolet irradiation or Fenton’s reagent.
相关工作介绍（推荐阅读）：
1. 在H2O2存在的情况下合成易于分离的bulk TS-1，出自浙大肖丰收教授课题组，作用机制可能与本文差不多（ChemCatChem 2010, 2, 407-412.）
2. DFT计算：OH自由基对Si-O-Si键解离的催化作用（R. Konecny, J. Phys. Chem.B 2001, 105, 6221–6226）
2. 厦门大学王野老师的新作Angew. Chem. Int. Ed. DOI: 10.1002/anie.201601208
一句话评述：与包院士前几天的Science基本同时出品，整体思路也差不多，所谓英雄所见略同吧。
The direct synthesis of lower (C2 to C4) olefins, key building-block chemicals, from syngas (H2 /CO), which can be derived from various nonpetroleum carbon resources, is highly attractive, but the selectivity for lower olefins is low because of the limitation of the Anderson–Schulz–Flory distribution. We report that the coupling of methanol-synthesis and methanol-to-olefins reactions with a bifunctional catalyst can realize the direct conversion of syngas to lower olefins with exceptionally high selectivity. We demonstrate that the choice of two active components and the integration manner of the components are crucial to lower olefin selectivity. The combination of a Zr–Zn binary oxide, which alone showshigher selectivity for methanol and dimethyl ether even at 673 K, and SAPO-34 with decreased acidity offers around 70 % selectivity for C2–C4 olefins at about 10 % CO conversion.The micro- to nanoscale proximity of the components favors the lower olefin selectivity.
相关文献推荐：包老师的Science才出几天，上周才分享给大家，不多介绍（Science, 2016, 351, 1065-1068）
3. 按惯例分享J.Catal.一篇，一句话评述：FeCx被认为是Fe/HZSM无氧芳构化的活性物种，它可以稳定芳构化中间体卡宾。
Catalytic dehydroaromatization of methane has been investigated over 2–6 wt.% Fe-modified HZSM-5 or HMCM-22 zeolite in the absence of an added oxidant. After pretreatment in a CH4/Ar/He mixture, Fe/HMCM-22, and more significantly, Fe/HZSM-5 exhibited high catalytic activity in nonoxidative conversion of methane to aromatic hydrocarbons. This conversion actually takes part in three consecutive steps, oxidation of methane by iron oxides, decomposition, and aromatization of methane. During this conversion, XPS and XRD results showed the gradual reduction of Fe2O3 to metallic Fe, followed by the carburization of the metallic species. The fact that no aromatic products were detected until iron carbide was formed demonstrated that carburized Fe was the active species for the aromatization ofmethane. Under the same reaction conditions, both metallic Fe and carburized Fewere highly effective for activation of methane, but they catalyzed dehydrogenation of methane to carbonaceous materials and to aromatics, respectively. Differencein the catalytic properties of those two Fe species suggested that carburized Fe could stabilize carbene, the primary intermediate of activated methane, possibly via formation of a metal–carbene complex, C-Fe=CH2, so that carbene was able to dimerize into ethylene, which was then oligomerized to aromatics onthe acid sites of the zeolite.
无氧芳构化文献推荐：
包院士2014年发的Science, 甲烷转化率高达48.1%，乙烯选择性为48.4%, 积碳不足1% (Science 2014, 344, 616-619)
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