Molecular-level insight into photocatalytic reduction of N2 over Ruthenium single atom modified TiO2 by electronic Metal-support interaction

The sustainable production of NH3 by fixing N-2 under mild conditions via photocatalysis is fascinating compared to current industrial processes operated at critical conditions. However, the inert N-2 is extremely difficult to adsorb and activate. And the transfer of photogenerated electrons to the NN bond is energetically challengeable. Herein, we presented a photocatalyst designed based on electronic metal-support interactions (EMSI), which proved to be a reliable strategy for improving the photocatalytic N-2 fixation performance. The introduction of Ru single atoms into TiO2 by a molten salt method can stabilize the oxygen vacancies, thus achieving an ammonia yield rate of 18.9 mu mol.g(-1).h(-1) under mild conditions without any sacrificial agent due to the significant enhancement of EMSI. The combination of experimental results with first-principles simulations confirmed that the EMSI can tune the local atomic structure and accelerate the transfer of photogenerated carriers between Ru single atoms and TiO2 carriers, thus effectively enhancing photocatalytic N-2 reduction activity. Additionally, the alternating pathway is more favored route for NH3 formation on the optimized single atom Ru/TiO2. Our atomic-level design and mechanistic studies provided a new reference for efficiently photocatalytic nitrogen fixation.