配体功能化MIL-101(Fe)金属有机骨架的制备及光催化还原CO2性能OA

Solar-driven photocatalytic reduction of CO2 into high-value-added chemicals(e.g.,formic acid,methanol)represents a cutting-edge strategy for mitigating the greenhouse effect and achieving carbon resource recycling.A series of ligand-functionalized X-MIL-101(Fe)MOFs catalytic materials was prepared by introducing functional groups such as—NH2,—OCH3,—Br and—NO2 by one-pot solvothermal method.The morphology,structure and optoelectronic properties of the catalysts were characterized by X-ray diffractometer(XRD),element analyzer(EA),scanning electron microscope(FE-SEM),ultraviolet-visible absorption spectroscopy(UV-Vis),photocurrent response spectroscopy(I-t),electrochemical impedance spectroscopy(EIS)and fluorescence emission spectroscopy(PL).The study demonstrates that the electronic properties of functional groups significantly modulate the light absorption,band structure,and charge carrier behavior of material:electron-donating groups(—NH2,—OCH3)enhance light response and promote charge separation;electron-withdrawing groups(—Br,—NO2)suppress light absorption and electron transfer.The—NH2 group exhibits a stronger electron-donating ability than the—OCH3 group bonded to the benzene ring.Consequently,under simulated sunlight,amino-modified NH2-MIL-101(Fe)demonstrated optimal photocatalytic performance for CO2 reduction,exhibiting the strongest photocurrent response and highest charge separation efficiency.In pure water,its formic acid production rate reached 28.13 µmol·g-1·h-1,which further increased to 42.61 µmol·g-1·h-1 with the addition of a sacrificial agent,representing a 3.45-fold improvement over unmodified MIL-101(Fe).The material also demonstrated excellent reusability,maintaining 93.92%of its activity after four cycles.This study provides theoretical foundations and experimental references for designing highly efficient and stable MOF-based CO2 photoreduction catalysts from the perspectives of the ligand structure.