Direct Synthesis, Structural Features, and Enhanced Catalytic Activity of the Basolite F300-like Semiamorphous Fe-BTC Framework
作者:Manuel Sanchez-Sanchez、Iñigo de Asua、Daniel Ruano、Kenya Diaz
DOI:10.1021/acs.cgd.5b00755
日期:2015.9.2
Paradoxically, one of the most widely and successfully tested metal–organic framework (MOF)-based catalysts, i.e., the Fe-BTC material commercialized as Basolite F300, entails a certain “mystery”: Its structure is unknown and only an indirect and complex preparation method has been reported. This work describes an easy preparation method of a Basolite F300-like material. Furthermore, this synthesis procedure is carried out under environmentally and economically sustainable conditions: at room temperature, in a few minutes and using water as the unique solvent. Several characterization techniques indicate that both commercial and lab-made Fe-BTC materials are very much similar in so many physicochemical properties. However, the herein reported Fe-BTC possesses better textural properties, especially regarding the external surface area. Both Fe-BTC materials catalyze the oxidation of cyclohexene with very similar selectivity. However, the sample prepared in the laboratory gives a notably higher conversion, which was attributed to its external surface area. Iron leaching, if any, was negligible, and no significant structural transformation was detected. Finally, this paper also gives valuable structural information about the semiamorphous Fe-BTC: it exclusively contains the smallest mesocages of MIL-100(Fe), which provides an important input for interpreting the role of these Fe-BTC materials in any application demanding high porosity.
具有讽刺意味的是,Fe-BTC材料(商业化名为Basolite F300)是最广泛且成功测试的金属-有机框架(MOF)催化剂之一,但其结构仍然未知,且仅有间接和复杂的制备方法被报道。本文描述了一种类似Basolite F300材料的简便制备方法。此外,这一合成过程在环境友好和经济可持续的条件下进行:在室温下,用几分钟时间,使用水作为唯一溶剂。多种表征技术表明,商业化和实验室合成的Fe-BTC材料在许多物理化学性质上非常相似。然而,本文报道的Fe-BTC具有更佳的结构特性,特别是在外表面积方面。两种Fe-BTC材料催化环己烯的氧化反应,选择性非常相似。然而,实验室制备的样品在转化率上显著更高,这归因于其外表面积。铁的浸出若存在也微乎其微,并且未检测到显著的结构转变。最后,本文还提供了关于半无定形Fe-BTC的宝贵结构信息:它仅包含MIL-100(Fe)的最小中孔,这为理解这些Fe-BTC材料在任何高孔隙度应用中的角色提供了重要依据。