Excitonic Au4Ru2(PPh3)2(SC2H4Ph)8 cluster for light-driven dinitrogen fixation

The surface plasmon resonance of metal nanoparticles has been widely used to improve photochemical transformations by plasmon-induced charge transfer. However, it remains elusive for the molecular-like metal clusters with non-metallic or excitonic behavior to enable light harvesting including electron/hole pair production and separation. Here we report a paradigm for solar energy conversion on an atomically precise Au4Ru2 cluster supported on TiO2 with oxygen vacancies, in which the electron-hole pairs can be directly generated from the excited Au4Ru2 cluster and the TiO2 support, and the photogenerated electrons can transfer to the Ru atoms. Importantly, the Ru atoms in the Au4Ru2 cluster are capable of injecting the electrons into adsorbed N2 to activate N2 molecules. The cooperative effect in the supported Au4Ru2 catalyst efficiently boosts the photocatalytic activity for N2 fixation in comparison with homogold (Aun) clusters.