Highly stable nitrogen-doped carbon nanotubes derived from carbon dots and metal-organic frameworks toward excellent efficient electrocatalyst for oxygen reduction reaction

A highly efficient nitrogen-doped carbon nanotubes (N-CNTs) electrocatalyst derived from nitrogen-doped carbon dots (N-Cdots) and metal-organic frameworks (MOFs) for oxygen reduction reaction (ORR) was demonstrated successfully for the first time. The N-Cdots with plenty of hydroxyl and amine groups can favor the formation of N-CNTs through the catalytic decomposition of MOFs in a lower temperature. On the other hand, the N-Cdots serve as inducers of the graphitic structure and supply extra nitrogen, extending a potential electrocatalytic activity of N-CNTs. Results show that the N-CNTs provided an excellent ORR electrocatalytic performance, yielding a positive onset potential of 0.88 V vs. RHE and a high kinetic current density of up to 5.58 mA cm−2 at 0.2 V. In addition, the slope of N-CNTs being ∼81 mV/dec can be found to be much lower than that of the Pt/C catalyst (∼132 mV/dec). These superior performances are attributed to defects in the graphitic crystal structure and the synergistic coupling effects of N-Cdots and N-CNTs. In addition, a slight loss in activity for the N-CNTs catalyst can be found whereas the Pt/C catalyst decreases nearly 45% of its initial activity, which exhibit highly catalytic durability and tolerance to methanol in an alkaline media.