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*).