A microporous mixed-metal (Na/Cu) mixed-ligand (flexible/rigid) metal-organic framework for photocatalytic H-2 generation

摘要

For the first time, we report a cost-effective mixed-metal (Na/Cu) mixed-ligand (flexible/rigid) metal-organic framework H-1.5[Na0.5Cu2(L-1)(L-2)(H2O)]center dot 5.5H(2)O (Na/Cu-MOF; H2L1 = 4,4 '-(4-(4H-1,2,4-triazol-4-yl)phenylazanediyl)dibenzoic acid; and H4L2 = citric acid). The 3D microporous framework of the Na/Cu-MOF consists of 10.28 angstrom x 10.07 angstrom quadrilateral channels and 14.52 angstrom x 6.72 angstrom triangular channels, which exhibits highly efficient photocatalytic H-2 generation (4650 mu mol g(-1) h(-1)) under visible-light irradiation. Emission quenching and transient photocurrent experiments confirm the charge separation and transfer process for the possible reaction mechanism in the photocatalytic system. Control experiments using a similar single-metal single-ligand MOF [Cu-2(L-2)(H2O)(2)] (Cu-MOF; H4L2 = citric acid) have been performed for comparison, which demonstrates the potential of mixed-metal mixed-ligand MOFs in the practical utilization of light.