Selective
phenol hydrogenation is a valuable route to produce cyclohexanone,
but it poses a great challenge. Herein, a series of Pd@PC-COFs catalysts
were prepared by the wet impregnation with different solvents. The
impregnation solvent has a great influence on the microstructures
and surface characteristics of the Pd@PC-COFs catalysts and their
catalytic properties in the selective phenol hydrogenation to cyclohexanone.
The as-prepared Pd@PC-COF-NBA catalyst shows the highest catalytic
activity, with a phenol conversion of 98.3% at the cyclohexanone selectivity
of 98.9%, which is 5.3 times that of Pd@PC-COF-MeOH and 2.4 times
that of Pd@PC-COF-DI. Larger specific surface area, well-developed
pore structures, rich mesoporous ratio, higher Pd content and Pd(0)
ratio, and improved Pd dispersion are the important reasons for the
superior catalytic performance of Pd@PC-COF-NBA. Pd@PC-COF-EA and
Pd@PC-COF-Dio exhibit good catalytic stability during five reaction
cycles. These findings can aid the development of high-performance
Pd@COFs for the selective phenol hydrogenation.