Bio-inspired Fe/Ti-MOF photocatalysts for efficient nitrogen fixation under mild conditions

Photocatalytic nitrogen fixation as a green, environmentally friendly, mild and low energy-consuming nitrogen fixation is considered as an ideal way to produce ammonia. Herein, inspired by nitrogen-fixing enzymes, the MOF materials Fe-sdc and Ti-sdc were synthesized by a simple solvothermal synthesis method using Fe and Ti as metal nodes and 4,4′-stilbenedicarboxylic acid (H₂sdc) as a ligand. The ammonia production rates of Fe-sdc and Ti-sdc were 61.01 μmol g⁻¹ h⁻¹ and 46.84 μmol g⁻¹ h⁻¹. The ¹⁵N₂ isotope experiments were utilized to determine the nitrogen source for ammonia synthesis during the nitrogen fixation process of Fe-sdc. Various characterization analyses were also utilized to analyze the reasons for the better nitrogen fixation performance of the two catalysts.