A synergistic strategy of hierarchical pore engineering and ligand functionalization: Modulating Ni sites in Ce-UiO-66 for dicyclopentadiene hydrogenation under mild conditions

Abstract

The development of catalytic activity for non-noble metals at low temperature features significant value for green chemical production with high economic interest. This work has successfully customized a series of ligand-functionalized and hierarchically porous Ce-UiO-66-X (HP-U(Ce)-X, -X= -NH2, -H, -NO2, -Br) as supports through the soft template methods, achieving the organic combination of bifunctional structures, providing abundant mesoporous channels for high exposure of guest Ni sites and efficient mass transfer of reaction substrates. The presence of electron-withdrawing/donating groups also facilitates electronic structure modification of Ni species. Therefore, with the selection of optimal -Br and synergistic improvement of mesoporous structures by formic acid (FA) and nitric acid (HNO3), Ni loaded on HP-U(Ce)-Br-6-4 obtains the lowest electron density and outstanding accessibility, reaching 100% conversion of dicyclopentadiene (DCPD) and ~100% selectivity for tetrahydrodicyclopentadiene (THDCPD) in only 30 min at 70 ℃ (while selectivity up to 95% at 60 ℃). This study provides new insight and guidance for performance modulation of non-noble metal based catalysts and rational integration of multifunctional structures in porous materials.