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.