Cobalt supported nitrogen-doped carbon nanotube as efficient catalyst for hydrogen evolution reaction and reduction of 4-nitrophenol

Abstract

Transition metal-supported carbon hybrid structures have evolved for various catalytic applications. However, few studies have reported the use of the same catalyst for both electrochemical hydrogen evolution reaction (HER) and chemical reduction of 4-nitrophenol (4-NP) with excellent catalytic performance and long-term stability. Herein, we present a facile approach to obtain cobalt nanoparticles supported by nitrogen-doped carbon nanotube (Co@N-CNT) with yarn bundle morphology. The use of zeolitic-imidazolate frameworks (ZIFs) is an easy approach to control and design a desired hybrid structure under 5% H2/Ar at 900 °C due to selective metal ions with an organic linker. In particular, the number of catalytic active sites in cobalt metal and the high conductance of carbon showed a synergetic effect and turned the hybrid structure into an optimal catalyst candidate for HER and reduction of 4-NP. In addition, interfacial physicochemical interaction within the N-CNT and Co metal promptly accelerated the electrocatalytic performance at overpotential of 44 mV and achieved a current density of 10 mA cm−2 with continued running of stability cycles for 30 h. Furthermore, a pseudo-first-order kinetic constant of 0.68 min−1 was achieved for the reduction of 4-NP.