Regulating the production distribution in Ni-Cu nanoparticle mediated nitrile hydrogenation

The selective hydrogenation of nitrile compounds represents a pivotal area of research within both industrial and academic catalysis. In this study, we prepared Ni-Cu bimetallic catalysts through a co-deposition-crystallization sequence, aimed at the efficient production of primary and secondary amines. The enhanced selectivity for primary amines is attributed to the downshift of the d-band center of Ni 0.1 Cu, which weakens the adsorption of key imine intermediates. Consequently, the synthesized Ni-Cu catalysts demonstrated exceptional catalytic performance in the selective hydrogenation of nitrile compounds, including those with reduction-sensitive functional groups such as −Cl and −Br, achieving 100 % conversion efficiency and significant yields ranging from 80 % to 99 %. The reaction conditions were comprehensively optimized, taking into account factors such as temperature, solvent, time, additives, and hydrogen pressure. Furthermore, the catalytic performance of Ni 0.1 Cu and Ni 0.4 Cu in the selective hydrogenation of nitriles was sustained over at least five reaction cycles. Temperature-programmed desorption results elucidated the structure–activity relationship, revealing that a strong interaction site prevails in Ni 0.4 Cu, while a weaker or moderate interaction site in Ni 0.1 Cu is responsible for the formation of primary amines. Theoretical calculations indicate that the reaction proceeds via an imine mechanism, with benzylideneimine serving as a key intermediate. This work may stimulate further research into the development of bimetallic nano-catalysts for selective nitrile hydrogenation in industrial catalytic processes.