Morphological and heterojunctional engineering of two-dimensional porous Mo-Ni based catalysts for highly effective catalytic reduction of aromatic nitro compounds

Hydrogenation reactions play crucial roles on chemical synthesis and pollutant elimination. The improvement of the ability to activate reactants and increase of the contact probability between the catalysts and reactants are positive to improve the catalytic performance. Herein, we have reported the design of two-dimensional porous Ni-Ni3N-NiMoN heterojunction sheets (2D Mo-Ni based nanosheets) for efficient catalytic hydrogenation of the aromatic nitro-compounds. The heterojunction interfaces provide plentiful active sites to improve the activating ability of the catalyst on the reactants. Additionally, the 2D porous structure facilitates not only the contact of catalytic sites with reactants but also mass transfer and diffusion, both of which are favorable to accelerating the hydrogenation process. As a result, the optimized sample of 2D Mo-Ni sheet exhibits good activity for the hydrogenation of aromatic nitro-compounds by converting 0.2 mmol/L (30 mL) of p-nitrophenol to p-aminophenol within 45 s with good recyclability. The activation energy and the reaction rate at 25 oC is 31.11 kJ/mol and 0.0796 s-1, respectively, both of which surpass most of reported non-noble metal catalysts and rivals with most noble metal-based catalysts. The combination of late and early transition metals provides an innovative way to obtain outstanding catalysts for the hydrogenation.