SiO₂-template synthesis of mesoporous MgF₂ highly effective for Cl/F exchange reaction

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• 作者：Miao Chen^a ; ^{chenmiao@sinochem.com} ; Jia-Min Jin^a ; Sheng-Da Lin^a ; Ying Li^b ; Wu-Can Liu^a ; Li Guo^a ; Ling Li^a ; Xiao-Nian Li^b
• 关键词：Magnesium fluoride ; Silica-template ; High surface area ; Chlorodifluoromethane dismutation ; Lewis acidity
• 刊名：Journal of Fluorine Chemistry
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：150
• 期：Complete
• 页码：46-52
• 全文大小：1382 K

文摘

An efficient and cost-effective route has been developed for the controllable synthesis of high-surface-area MgF₂ materials with variable surface acidity and improved catalytic performance for Cl/F exchange reaction. This route is based on a facile non-surfactant template method, in which MgO-SiO₂ precursors were obtained at varied Si/Mg ratios via ammonia coprecipitation in aqueous media, followed by depletion of the SiO₂ template in 40 % aqueous HF solution. The thus-derived MgF₂ is featured with superior surface area, uniform mesopores, and significantly improved Lewis acidity relative to conventional MgF₂. Among samples synthesized, that with Si/Mg molar ratio at 1/6 achieved the highest surface area amounted to 92 m²/g after calcination at 573 K. Probe reaction by CHClF₂ dismutation has demonstrated far superior Cl/F exchange activities for SiO₂-templated MgF₂ samples relative to their non-templated analog, as may be accounted for by the combined effect of promoted surface properties and significantly enhanced surface acidity.