Accelerated crystallization of zeolites via hydroxyl free radicals
Accelerated crystallization of zeolites via hydroxyl free radicals
复制标题
通过羟基自由基加速沸石结晶
DOI：
10.1126/science.aaf1559
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发表时间：
2016-03-11
期刊：
影响因子：
56.9
通讯作者：
Yu, Jihong
中科院分区：
文献类型：
--
作者：
Feng, Guodong;Cheng, Peng;Yu, Jihong
在碱性介质中沸石的水热结晶过程中，氢氧根离子（OH⁻）通过断裂Si、Al - O - Si、Al键来催化铝硅酸盐凝胶的解聚，并通过重新形成Si、Al - O - Si、Al键来催化水合阳离子周围的铝硅酸盐阴离子的聚合。我们报道羟基自由基（·OH）参与了水热条件下的沸石结晶。沸石（如Na - A、Na - X、NaZ - 21和Silicalite - 1）的结晶过程可以通过紫外线照射或芬顿试剂产生的羟基自由基来加速。
Radically faster synthesis Zeolite synthesis normally proceeds under basic conditions that allow the oxide bridges between aluminum and silicon atoms to break and reform. Feng et al. show that the formation of hydroxyl radicals, either by irradiation with ultraviolet light or with the Fenton reagent, can speed up the formation of the crystallized zeolite by about a factor of 2. Science, this issue p. 1188 Hydroxyl radicals generated with ultraviolet light or Fenton reagents can approximately double the rate of zeolite synthesis. 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.