Highly-efficient RuNi single-atom alloy catalysts toward chemoselective hydrogenation of nitroarenes.

The design and exploitation of high-performance catalysts have gained considerable attention in selective hydrogenation reactions, but remain a huge challenge. Herein, we report a RuNi single atom alloy (SAA) in which Ru single atoms are anchored onto Ni nanoparticle surface via Ru-Ni coordination accompanied with electron transfer from sub-surface Ni to Ru. The optimal catalyst 0.4% RuNi SAA exhibits simultaneously improved activity (TOF value: 4293 h -1 ) and chemoselectivity toward selective hydrogenation of 4-nitrostyrene to 4-aminostyrene (yield: >99%), which is, to the best of our knowledge, the highest level compared with reported heterogeneous catalysts. In situ experiments and theoretical calculations reveal that the Ru-Ni interfacial sites as intrinsic active centers facilitate the preferential cleavage of N-O bond with a decreased energy barrier by 0.28 eV. In addition, the Ru-Ni synergistic catalysis promotes the formation of intermediates (C 8 H 7 NO* and C 8 H 7 NOH*) and accelerates the rate-determining step (hydrogenation of C 8 H 7 NOH*).