Engineering the Structure of ZIF-Derived Hierarchically Porous CoZn Catalysts for Efficient Selective Hydrogenation of Nitroarenes

ZIF-derived metal/carbon materials have received great attention for heterogeneous catalysis because of their versatile tunability; however, most of them are microporous-dominated structures, seriously limiting their catalytic performance. Herein, we directly synthesized CoZn@CN catalysts with high specific surface area and pore volume via the facile pyrolysis of CoZn-ZIF/g-C3N4@PDA composites (g-C3N4, graphitic carbon nitride; PDA, polydopamine), in which g-C3N4 works as the pore-forming agent and template and PDA mainly functions as the carbon source. The optimal catalyst (Co4Zn2@CN) exhibits superior specific surface area (825.0 m2/g) and pore volume (2.4 cm3/g), which can remarkably improve the mass transfer efficiency and boost the active site exposure, achieving a TOF of 34.5 h–1 for the selective hydrogenation of 3-nitrostyrene at 80 °C and 1 MPa H2. Additionally, the preferential adsorption of the nitro group is confirmed to be the main reason for the general selectivity in the hydrogenation of various functionalized nitroarenes. Finally, the Co4Zn2@CN catalyst also shows excellent stability and can be reused at least 5 times. We anticipate that such a novel strategy may provide some valuable insights into the synthesis of ZIF-derived catalysts with tunable structures.