Enhancing electron penetration through carbon shell of encapsulated catalysts by Co alloying for aromatic nitrobenzene hydrogenation

Abstract

Encapsulated catalysts have become a new strategy for catalysis in harsh reaction environments due to their unique structural and functional reorganization properties, and they have been widely applied in fields such as electrocatalysis, photocatalysis, and thermocatalysis. In strategies involving encapsulated catalysts, the optimization of electronic properties on the carbon layer surface to enhance reactivity while maintaining adequate encapsulation poses a challenge due to the trade-off between stability, poison resistance, and acid resistance against the performance of metal nanoparticles. Herein, an alloying strategy for Co-Ni bimetal was proposed, which achieves a delicate balance between catalyst activity and stability. Ni plays a pivotal role in promoting the formation of graphitized carbon and the construction of an effective encapsulation structure, thereby ensuring the stability of the catalyst. Co incorporation and alloying with Ni modulates the electronic state and D-band structure within the metallic core, effectively breaking the electronic cloud segregation barrier imposed by the carbon shell. This modulation notably enhances the efficiency of reactions. For the hydrogenation of p-CNB to p-CAN, Co₂Ni₈@C exhibits an extremely low apparent activation energy (53.40 KJ/mol), as well as > 99 % conversion and selectivity.