Chemoselective Hydrogenation of Nitroarenes at Room Temperature: Synergistic Effect of Ni and Mo Sites in Ni ₄ Mo Alloys

Developing cost-efficient catalysts for the chemoselective hydrogenation of nitroarenes is very important but quite challenging. Herein, the Mo alloying strategy was reported for tuning the activity and selectivity of cheap Ni catalysts for chemoselective hydrogenation of nitroarenes at room temperature. By alloying Ni with oxophilic Mo to generate the Ni4Mo alloy, the adsorption of the −NO2 group and dissociation of H2 on the surface of Ni4Mo were significantly enhanced, thus facilitating chemoselective adsorption and effective hydrogenation of the −NO2 group. The Ni4Mo sites were identified as the active centers, in which Ni and Mo atoms were responsible for the adsorption and activation of H2 and −NO2 groups, respectively. Taking the chemoselective hydrogenation of 4-nitrostyrene as an example, theoretical calculations revealed that the adsorption energy of the −NO2 group on the Ni4Mo(121) surface was much stronger than that of the vinyl group, leading to chemoselective hydrogenation of the −NO2 group. Moreover, the distinct electron densities on Ni and Mo facilitate the dissociation of H2 and the removal of O in the −NO2 group, accelerating the chemohydrogenation of the −NO2 group. This work provides insights into tuning the activity and selectivity of nonnoble metal catalysts by intermetallic alloying and can inspire the development of cost-effective catalysts for some challenging organic transformations.