N-Doped Graphene Supported Cu Single Atoms: Highly Efficient Recyclable Catalyst for Enhanced C-N Coupling Reactions

Heterogenization of homogeneous catalysis through supported single-atom catalysts (SACs) provided a feasible solution to recycling catalysts while keeping its efficiency in chemical synthesis. In this work, Cu SACs anchored on N-doped graphene (Cu SACs/NG) were prepared and first used for C-N coupling reactions. During the preparation, Cu-N-C structures, including Cu-N-4 moieties, were formed in a one-step pyrolysis method. As-prepared Cu SACs/NG exhibited excellent catalytic activity toward C-N coupling reactions with a broad scope of substrates and showed outstanding performance of recycling. Compared with Cu nanoparticles (Cu NPs/NG), the advantages of single-atom catalysts were validated via experimental and theoretical calculations. The enhanced performances were attributed to increasing the number of active sites and increasing the intrinsic activity of each active site. This work provides an alternative synthetic strategy for fabricating atomically dispersed SACs and represents a significant advance for coupling reactions.

Automated summary

In this study, copper single-atom catalysts supported on N-doped graphene were successfully used for C-N coupling reactions, displaying excellent catalytic activity and recyclability. Experimental and theoretical calculations confirmed the advantages of single-atom catalysts over copper nanoparticles, as they increased the number of active sites and improved the intrinsic activity of each active site. This work provides an important synthetic strategy for coupling reactions.