Enhanced Photocatalytic Nitrogen Fixation over Nano-UiO-66(Zr) via Natural Chlorophyll Sensitization

Metal-organic frameworks (MOFs) are potential semiconductor materials, but they still face limitations, such as insufficient photoresponse, high recombination rates, and inadequate N₂ adsorption/activation capabilities. Herein, a UiO-66-based system is designed via a natural chlorophyll sensitization strategy. Density functional theory calculations confirm the coordination interactions between chlorophyll and UiO-66. The chlorophyll-sensitized UiO-66 (Chlor@UiO-66) exhibits an improved NH₃ production rate of 73.1 μmol g^-1 h^-1, compared to UiO-66 (6.3 μmol g^-1 h^-1). This enhancement is attributed to the dye properties of chlorophyll and the electron-donating effect of the structure, which broadens the visible light absorption range and facilitates charge carrier separation and transfer, as well as N₂ adsorption/activation. In situ FT-IR characterization combined with theoretical calculations demonstrates that the reduction of N₂ at the Chlor@UiO-66 surface follows the alternating hydrogenation pathway. This research provides new insights for the design and synthesis of novel natural chlorophyll-sensitized nanomaterials for the photocatalysis of small molecules.