Carbon nanotube-supported Co-N-C with enriched mesopores for hydrogenation of nitro compounds

Abstract

Developing noble metal-free catalysts that enable hydrogenation reduction of nitro compounds to perform under mild conditions is highly attractive yet remains a significant challenge. Herein, carbon nanotube-supported Co-N-C with abundant mesopores (Co₁/CoNPs@CNT) was synthesized via in situ pyrolysis of zeolitic imidazolate framework-67 encapsulated ZnO (ZnO@ZIF-67) for catalytic hydrogenation. The Co₁/CoNPs@CNT catalyst features abundant atomically dispersed CoNx active sites that are easily accessible to substrates. Additionally, theoretical calculations suggest CoNx on curved surfaces favours the H₂ dissociation and the second NO bond breaking (PhNOH* + H* → PhN* + H₂O) more than that on flat surfaces, two crucial steps in the hydrogenation of nitro compounds. As a result, Co₁/CoNPs@CNT exhibits outstanding catalytic performance, enabling the hydrogenation reaction to go smoothly under mild conditions (50 °C, 1 bar H₂) with high conversion and selectivity across a range of substrates.