催化作用
路易斯酸
布朗斯特德-洛瑞酸碱理论
选择性
色散(光学)
材料科学
化学
化学工程
核化学
有机化学
工程类
物理
光学
作者
Wendy Zhang,Zichun Wang,Aleksei N. Marianov,Yuxiang Zhu,Lizhuo Wang,Patrice Castignolles,Marianne Gaborieau,Alfons Baiker,Jun Huang,Yijiao Jiang
标识
DOI:10.1002/cssc.202400128
摘要
WOx/ZrO2 with a higher concentration of Brønsted acid sites (BAS) and a bigger ratio of Brønsted to Lewis acid sites (B/L) than achievable by conventional impregnation (IM) were synthesized using flame spray pyrolysis (FSP). The rapid quenching and short residence time inherent to FSP prevent the accumulation of W atoms on the ZrO2 support and thus provide an excellent surface dispersion of WOx species. As a result, FSP‐made WOx/ZrO2 (FSP‐WOx/ZrO2) has a much higher surface concentration of three‐dimensional Zr‐WOx clusters than corresponding materials prepared by conventional impregnation (IM‐WOx/ZrO2). The coordination of W‐OH to the unsaturated Zr4+ sites in these clusters results in a remarkable decrease of the concentration of Lewis acid sites (LAS) on the surface of ZrO2 and promotes the formation of bridging W‐O(H)‐Zr hydroxyl groups acting as BAS. FSP‐WOx/ZrO2 possesses ~80% of BAS and a B/L ratio of around 4, while IM‐WOx/ZrO2 exhibits ~50% BAS and a B/L ratio of around 1. These catalysts were evaluated in the dehydration of glucose to HMF. The catalytic study demonstrated that B/L ratio plays a crucial role in glucose conversion. The best catalyst, FSP‐WOx/ZrO2 with a W/Zr ratio of 1/10 affords nearly 100% glucose conversion and an HMF selectivity of 56‐69%.
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