posted on 2024-02-17, 17:08authored byXianting Du, Wanchun Duan, Yanan Gao, Tong Wang, Tairan Li, Yunxiang Lin, Zhi-peng Yu, Kun Xu
The
study of structural reconstruction is vital for the understanding
of the real active sites in heterogeneous catalysis and guiding the
improved catalyst design. Herein, we applied a copper nitride precatalyst
in the nitroarene reductive coupling reaction and made a systematic
investigation on the dynamic structural evolution behaviors and catalytic
performance. This Cu3N precatalyst undergoes a rapid phase
transition to nanostructured Cu with rich defective sites, which act
as the actual catalytic sites for the coupling process. The nitride-derived
defective Cu is very active and selective for azo formation, with
99.6% conversion of nitrobenzene and 97.1% selectivity to azobenzene
obtained under mild reaction conditions. Density functional theory
calculations suggest that the defective Cu sites play a role for the
preferential adsorption of nitrosobenzene intermediates and significantly
lowered the activation energy of the key coupling step. This work
not only proposes a highly efficient noble-metal-free catalyst for
nitroarenes coupling to valuable azo products but also may inspire
more scientific interest in the study of the dynamic evolution of
metal nitrides in different catalytic reactions.