Implicating the Role of Au-H Bonds in Photochemical N2 Fixation by Ruthenium Doped Gold Clusters

Dinitrogen fixation through the Nitrogen Reduction Reaction (NRR) under mild conditions without the use of sacrificial agents has its share of formidable hurdles. It has been shown recently that Ru-doped Au nanoclusters can reduce N2 molecule to NH3 only in the presence of UV-Vis light in aqueous medium. Herein, using theoretical techniques (Density Functional Theory) we shed light on the mechanistic avenues traversed for achieving this prodigious chemical feat. Our findings suggest that the bimetallic Au22Ru6 cluster successfully accomplishes the NRR process under ambient pressure and temperature conditions by the very virtue of its bifunctional nature. Contrary to the existing views, we find that NRR propagates through an alternative associative pathway, where the Ru dopant assists in N2 adsorption while the Au-H bonds formed from Au assisted water splitting is implicated for facilitating NRR.