Engineering zirconium-based UiO-66 for effective chemical conversion of -xylose to lactic acid in aqueous condition
Utilizing metal-organic frameworks (MOFs) as heterogeneous catalysts is an interesting and important application due to their well-controlled catalytic sites and well-defined porous structures. In this study we apply, for the first time, Zr-based UiO-66 for the catalytic hydrothermal conversion of d...
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Published in | Chemical communications (Cambridge, England) Vol. 56; no. 58; pp. 819 - 822 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
21.07.2020
|
Online Access | Get full text |
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Summary: | Utilizing metal-organic frameworks (MOFs) as heterogeneous catalysts is an interesting and important application due to their well-controlled catalytic sites and well-defined porous structures. In this study we apply, for the first time, Zr-based UiO-66 for the catalytic hydrothermal conversion of
d
-xylose to lactic acid (LA). The reactions are catalyzed by the coordinatively unsaturated Zr
4+
, as Lewis acid sites, and the hydroxide ion (OH
−
) located at the defect sites. The catalytic performances of UiO-66 catalysts synthesized through a modulator-free approach (UiO-66) and an acetic acid modulator-assisted approach (UiO-66(AA)) are distinct due to the different concentrations of local defects. The UiO-66 catalyst possessing a higher defect concentration exhibits a superior LA yield of 1.17 mol from 1 mol of xylose. However, the UiO-66(AA) catalyst with higher crystallinity shows better selectivity for LA over furfural, a side product from the competitive pathway. The enhanced LA yield and excellent selectivity can be achieved by the removal of AA from UiO-66(AA) resulting in a novel MOF catalyst (UiO-66(AA)*) which provides more accessible catalytic sites with retained crystallinity. This work highlights that the structural engineering of MOF catalysts is crucial for the fine-tuning of their catalytic properties.
Local defects and crystallinity of UiO-66 were systematically engineered, yielding an effective catalyst for lactic acid production from
d
-xylose
via
a hydrothermal reaction. |
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Bibliography: | 10.1039/d0cc03424j Electronic supplementary information (ESI) available. See DOI |
ISSN: | 1359-7345 1364-548X |
DOI: | 10.1039/d0cc03424j |