Controllable Structure and Basic Sites of Pd@N-Doped\nCarbon Derived from Co/Zn-ZIFs: Role of Co

Abstract

Zeolite imidazolate frameworks (ZIFs)\nderivatives, porous N-doped\ncarbon (CN) materials, show outstanding performance when used as catalyst\nsupports. The characteristics of ZIFs affect significantly the microstructure\nof CN. In this work, a series of CN materials were fabricated through\ndirect pyrolysis of Zn/Co-ZIFs and Pd@CN catalysts were achieved by\nloading Pd nanoparticles. The results underline that the Co content\nin Zn/Co-ZIFs influences considerably the properties of CN and the\ncatalytic activity of Pd@CN for the phenol hydrogenation to cyclohexanone.\nN₂ adsorption–desorption, CO₂-TPD, and\nICP analyses confirm that the increase of Co in ZIFs can enhance significantly\nthe mesoporous ratio of CN for improving the loading and dispersion\nof Pd and increase the basic sites of CN materials for improving the\nphenol adsorption. As a result, significantly enhanced phenol conversion\nwith similar cyclohexanone selectivity is achieved. These findings\nprovide deep insights for the fabrication of ZIF-derived CN materials\nand their applications in catalysis.