Construction the Ni@Carbon nanostructure with dual-reaction surfaces for the selective hydrogenation reaction

The reduction of the size and modification the surface of Ni⁰ are generally used to improve the hydrogenation performances of Ni-based catalysts. In this work, a new method derived Ni⁰@carbon nanostructure was constructed on SiO₂ in order to explore an alternative way to improve the intrinsic activity of Ni⁰ in the selective hydrogenation of p-chloronitrobenzene (p-CNB). The experimental and computational results exhibit that the synergistic effect between Ni⁰ core and nitrogen-doped carbon shell (Ni⁰@C-N) can dissociate more hydrogen on larger Ni⁰ core (~14 nm) than Ni⁰@C (Ni⁰ ≈ 11 nm), while the external surface of carbon shell facilitates the oblique adsorption of p-CNB and the consequent hydrogenation. Such formed dual-reaction surfaces inhibit the dechlorination reaction but increase the active hydrogen species. Consequently, Ni⁰@C-N/SiO₂ catalyst (~14 nm) adversely displays ~2.3-fold higher turnover frequency and ~100% p-chloroaniline selectivity, in contrast to Ni⁰@C/SiO₂ (~11 nm) and the commercial Raney Ni (~6 nm) catalysts.