Zirconium-oxo Nodes of MOFs with Tunable Electronic Properties Provide Effective ⋅OH Species for Enhanced Methane Hydroxylation.

Authors :: Fang G
Hu JN
Tian LC
Liang JX
Lin J
Li L
Zhu C
Wang X
Source :: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2022 Sep 05; Vol. 61 (36), pp. e202205077. Date of Electronic Publication: 2022 Jul 27.
Publication Year :: 2022
Abstract: Direct conversion of methane to high value-added oxygenates under mild conditions has attracted extensive interest. However, the over-oxidation of target products is usually unavoidable due to the easily excessive activation of C-H bond on the sites of supported metal species. Here, we identified the most efficient Zr-oxo nodes of UiO-66 metal-organic frameworks (MOFs) catalysts for the selective oxidation of methane with H <subscript>2</subscript> O <subscript>2</subscript> . These nodes were modified by three types of benzene 1, 4-dicarboxylates (NH <subscript>2</subscript> -BDC, H <subscript>2</subscript> BDC, and NO <subscript>2</subscript> -BDC). Detailed characterizations and DFT calculations revealed that these ligands can effectively tune the electronic properties of Zr-oxo nodes and the H <subscript>2</subscript> BDC ligand led to optimal electronic density of Zr-oxo nodes in UiO-66. Thus the UiO-66-H catalyst promoted the formation of ⋅OH species that adsorbed on Zr-oxo nodes, and facilitated the activation of methane with a lower energy barrier and subsequent conversion to hydroxylation oxygenates with 100 % selectivity.<br /> (© 2022 Wiley-VCH GmbH.)

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