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Synthesis of Fluoride-Containing High Dimensionally Structured Nb Oxide and Its Catalytic Performance for Acid Reactions.
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2020-06-22 , DOI: 10.1021/acs.inorgchem.0c00949
Satoshi Ishikawa 1 , Mai Shinoda 1 , Yuta Motoki 1 , Shota Tsurumi 1 , Momoka Kimura 1 , Norihito Hiyoshi 2 , Akihiro Yoshida 3 , Wataru Ueda 1
Affiliation  

High dimensionally structured niobium oxide (HDS-NbO) containing fluoride (F) was prepared by a hydrothermal synthesis. F could be introduced into HDS-NbO by replacing lattice oxygen up to a solid F/Nb ratio of 0.55. The introduction of an appropriate amount of F promoted the crystal growth of HDS-NbO, while niobium oxyfluoride having the hexagonal tungsten bronze structure (HTB-Nb(F,O)x) was concomitantly formed by excess F addition. HAADF-STEM analysis suggested that the number of micropores (hexagonal and heptagonal channels) in HDS-NbO was increased by the introduction of an appropriate amount of F. The catalytic activity for Brønsted acid reactions was evaluated by Friedel–Crafts alkylation. The catalytic activity was significantly increased by the introduction of F, while excess introduction of F significantly decreased the activity. Catalytic activity for the Lewis acid reaction in the presence of water was evaluated by the transformation of pyruvaldehyde into lactic acid. The catalytic activity was changed by the introduction of F in a manner similar to that observed in the Friedel–Crafts alkylation. On the basis of the results obtained, we propose that the local catalyst structure around the micropores of HDS-NbO is crucial for the acid reactions.

中文翻译:

含氟高尺寸结构铌氧化物的合成及其对酸反应的催化性能。

高维结构化氧化铌(HDS-NBO)含氟化物(F - )通过水热合成制备的。可以通过取代晶格氧将F 引入HDS-NbO中,直至固体F / Nb比为0.55。引进的F适量-促进HDS-NbO构成的晶体生长,同时具有六方晶钨青铜结构(HTB-铌(F,O)氟氧化铌X)中的溶液伴随由过量˚F形成-除了。HAADF-STEM分析表明,通过引入适量的F –可以增加HDS-NbO中的微孔(六边形和七边形通道)数量。布朗斯台德酸反应的催化活性通过Friedel-Crafts烷基化评估。催化活性显著增加引入的F - ,而过量引入的F -显著降低的活性。通过将丙酮醛转化为乳酸来评估在水存在下对路易斯酸反应的催化活性。催化活性通过引入的F改变-在类似于在上述Friedel-Crafts烷基化中观察到的方式。根据获得的结果,我们提出HDS-NbO微孔周围的局部催化剂结构对于酸反应至关重要。
更新日期:2020-07-06
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