In-situ synthesis of ultrafine Co nanoparticles confined in interconnected nitrogen-doped carbon networks for enhanced reduction of 4-nitrophenol

Abstract

The integration of 3d transition metal nanoparticles with carbon materials holds great promise to rationally design and fabricate advanced catalysts. In this work, a 3D hybrid of ultrafine Co nanoparticles strongly confined in interconnected nitrogen-doped carbon networks (Co@INC) was synthesized by one-step pyrolysis of polypyrrole/zeolitic imidazole framework composites (PPy/ZIF-67), and then was evaluated as catalysts toward the reduction of 4-nitrophenol (4-NP). Both pyrolyzed Co2+-coordinated PPy and ZIF-67 contributed to generate a large amount of highly-dispersed Co nanoparticles, which ensured structural integrity and high content of N doping. Benefitting from the 3D interconnected carbon networks for large mass transfer and considerably exposed active sites, the Co@INC possessed remarkedly enhanced catalytic performance with almost 100% of 4-NP conversion within 120 s by adding 0.06 mg of catalyst. Meanwhile, it also held outstanding stability and reusability. These findings provide new insight into fabricating the 3D transition metal–carbon hybrids derived from MOFs-related materials for catalytic application.