Small interface with ample impact: Synergistic catalysis between Ni0 and Ni2+ during nitrobenzene hydrogenation

The development of Ni-based catalyst with simultaneous outstanding catalytic performance and low cost and the exploration of nitrobenzene hydrogenation mechanism are in urgent need but still remain a severe challenge. Herein, a nickel phyllosilicate (Ni@Si) catalyst in which Ni species are stabilized by SiOx ligands is successfully prepared and applied in nitrobenzene hydrogenation to obtain aniline, exhibiting excellent catalytic performance (∼97.6% yield). A combination study reveals that the Ni0 and Ni2+ species cooperatively catalyze the reaction and govern the catalytic performance of the rate-determining step, namely NO group reduction. Specifically, Ni0 species facilitates activation and dissociation of H2, while Ni2+ species accounts for the adsorption of NO group via the lone electron pairs in oxygen. This work would pave the way to the rational design of efficient Ni-based catalysts and deepen the fundamental understanding for nitrobenzene hydrogenation.