摘要: UiO-66-H MOFs can effectively catalyze the direct selective oxidation of methane (DSOM) to high value-added oxygenates under mild conditions. However, UiO-66-NH2 with benzene-1,4-dicarboxylate (NH2-BDC) ligand modifying the Zr-oxo nodes exhibits relatively inferior catalytic performance for DSOM. Here, a combination of density functional theory (DFT) calculations and experiments was employed to explore the underlying reasons for the limited catalytic activity of UiO-66-NH2. The results indicate that the methane hydroxylation performance of UiO-66-NH2 is almost unaffected by the increase of •OH concentration. This is attributed to the formation of substantial non-covalent hydrogen bonds between the oxygen atoms of oxygenic species on the Zr-oxo nodes and the hydrogen atoms of –NH2 groups, which diminishes the spin density distribution on the active sites of (•OH)m/UiO-66-NH2, leading to minimal change of the adsorption energy of CH4. Additionally, the calculated adsorption energies (Eads) of CH4 exhibit a linear relationship with the catalytic activity of UiO-66-NH2 for DSOM reaction.