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Sub-nano MgF2 embedded in carbon nanofibers and electrospun MgF2 nanofibers by one-step electrospinning as highly efficient catalysts for 1,1,1-trifluoroethane dehydrofluorination
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2017-11-06 00:00:00 , DOI: 10.1039/c7cy02056b Wenfeng Han 1, 2, 3, 4 , Chunpeng Zhang 1, 2, 3, 4 , Haili Wang 1, 2, 3, 4 , Shenglan Zhou 1, 2, 3, 4 , Haodong Tang 1, 2, 3, 4 , Luteng Yang 1, 2, 3, 4 , Zhikun Wang 1, 2, 3, 4
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2017-11-06 00:00:00 , DOI: 10.1039/c7cy02056b Wenfeng Han 1, 2, 3, 4 , Chunpeng Zhang 1, 2, 3, 4 , Haili Wang 1, 2, 3, 4 , Shenglan Zhou 1, 2, 3, 4 , Haodong Tang 1, 2, 3, 4 , Luteng Yang 1, 2, 3, 4 , Zhikun Wang 1, 2, 3, 4
Affiliation
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Hydrofluorocarbons (HFCs) which are usually potent greenhouse gases are regulated by the Montreal Protocol and its amendments, especially the recent Kigali Amendment. Dehydrofluorination of HFCs is an efficient route for the conversion of these greenhouse gases to value added and environmentally benign chemicals. Although AlF3 with strong Lewis acidity catalyzes dehydrofluorination, it also favors carbon deposition. MgF2 with weak acidity inhibits coking significantly. Unfortunately, MgF2 sinters dramatically at temperatures below 300 °C leading to the low activity for dehydrofluorination. In the present work, we report that sub-nano MgF2 embedded in carbon fibers and electrospun MgF2 fibers prevent sintering of MgF2 during dehydrofluorination reaction. Via simple and one-step electrospinning and calcination in a N2 (for embedded MgF2) or air (for MgF2 fibers) atmosphere, embedded MgF2 with particle sizes between 3–6 nm and pure MgF2 fibers with diameters of around 100 nm were fabricated. No sintering was observed following reaction at 450 °C. The fine MgF2 particles and MgF2 fibers facilitate the formation of under coordinated Mg species in MgF2 which are the weak acid sites. By embedding MgF2 or fabrication of MgF2 fibers, weak acid sites are increased significantly, while strong acid sites remain almost unchanged. Hence, they show significantly higher reaction rates than MgF2 prepared by precipitation of Mg(CH3COO)2·4H2O with NH4F for the dehydrofluorination of 1,1,1-trifluoroethane (HFC-143a) to VDF (CH2![[double bond, length as m-dash]](http://www.rsc.org/images/entities/char_e001.gif)
CF2) at 450 °C.
中文翻译：
一步法静电纺丝将亚纳米MgF 2嵌入碳纳米纤维和电纺MgF 2纳米纤维中，作为1,1,1-三氟乙烷脱氢氟化的高效催化剂
通常是强效温室气体的氢氟碳化合物（HFC）受《蒙特利尔议定书》及其修正案（尤其是最近的《基加利修正案》）的监管。HFC的脱氟化氢是将这些温室气体转化为增值产品和对环境无害的化学品的有效途径。尽管具有强路易斯酸度的AlF 3催化脱氟化氢，但它也有利于碳沉积。酸性弱的MgF 2显着抑制焦化。不幸的是，MgF 2在低于300°C的温度下会剧烈烧结，导致脱氟化氢活性低。在目前的工作中，我们报告了嵌入碳纤维中的亚纳米MgF 2和电纺MgF 2纤维防止在脱氟化氢反应过程中MgF 2的烧结。通过简单和一步静电纺丝和煅烧中，在N 2（用于嵌入式的MgF 2）或空气（为的MgF 2层的纤维）气氛下，将嵌入的MgF 2 3：00-6：nm和纯的MgF之间与粒径2种直径的大约100纤维纳米被制造。在450℃下反应后未观察到烧结。细的MgF 2颗粒和MgF 2纤维有助于在MgF 2中形成弱酸位的配位不足的Mg物种。通过嵌入MgF 2或制造MgF 2纤维中，弱酸性部位显着增加，而强酸性部位几乎保持不变。因此，它们显示出比通过用NH 4 F沉淀Mg（CH 3 COO）2 ·4H 2 O与NH 4 F沉淀而制备的MgF 2更高的反应速率，从而将1,1,1-三氟乙烷（HFC-143a）脱氟化氢成VDF（CH 2 CF 2）在450°C下。
更新日期：2017-11-16
CF2) at 450 °C.
中文翻译：
一步法静电纺丝将亚纳米MgF 2嵌入碳纳米纤维和电纺MgF 2纳米纤维中，作为1,1,1-三氟乙烷脱氢氟化的高效催化剂
通常是强效温室气体的氢氟碳化合物（HFC）受《蒙特利尔议定书》及其修正案（尤其是最近的《基加利修正案》）的监管。HFC的脱氟化氢是将这些温室气体转化为增值产品和对环境无害的化学品的有效途径。尽管具有强路易斯酸度的AlF 3催化脱氟化氢，但它也有利于碳沉积。酸性弱的MgF 2显着抑制焦化。不幸的是，MgF 2在低于300°C的温度下会剧烈烧结，导致脱氟化氢活性低。在目前的工作中，我们报告了嵌入碳纤维中的亚纳米MgF 2和电纺MgF 2纤维防止在脱氟化氢反应过程中MgF 2的烧结。通过简单和一步静电纺丝和煅烧中，在N 2（用于嵌入式的MgF 2）或空气（为的MgF 2层的纤维）气氛下，将嵌入的MgF 2 3：00-6：nm和纯的MgF之间与粒径2种直径的大约100纤维纳米被制造。在450℃下反应后未观察到烧结。细的MgF 2颗粒和MgF 2纤维有助于在MgF 2中形成弱酸位的配位不足的Mg物种。通过嵌入MgF 2或制造MgF 2纤维中，弱酸性部位显着增加，而强酸性部位几乎保持不变。因此，它们显示出比通过用NH 4 F沉淀Mg（CH 3 COO）2 ·4H 2 O与NH 4 F沉淀而制备的MgF 2更高的反应速率，从而将1,1,1-三氟乙烷（HFC-143a）脱氟化氢成VDF（CH 2 CF 2）在450°C下。
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