Synergy of metallic Cu and Cu3N species as dual active sites for enhanced hydrogenation catalysis

Chemoselective hydrogenation of quinoline and its derivatives is widely applicable in fine chemical production, yet it still faces grand challenges to obtain high activity and satisfactory selectivity simultaneously under mild conditions. In this study, we tuned the compositions of metallic Cu and Cu 3 N species by NH 3 treatment on CuO precursor at different temperatures. The specific catalyst after 375 °C treatment demonstrates excellent performance in the chemoselective hydrogenation of quinoline, achieving 98.8% conversion and >99% selectivity of 1,2,3,4-tetrahydroquinoline under mild reaction conditions (90 °C, 1 MPa), which significantly surpasses the performance of previously reported Cu-based catalysts. Moreover, the catalyst exhibits remarkable stability and substrate versatility. Various characterizations and DFT calculations reveal that there is obviously synergistic effect between metallic Cu and Cu 3 N species. Specifically, metallic Cu facilitates hydrogen dissociation, while Cu 3 N enhances the adsorption of quinoline molecules. These findings highlight the potential of Cu-based catalyst with dual active sites as a robust and efficient alternative for chemoselective hydrogenation.