CoNi nanocrystal anchoring on MOF derived carbon skeleton autocatalytic growth N-doped carbon nanotubes for efficient bifunctional electrocatalyst towards methanol oxidation/oxygen reduction

Abstract

In this paper, a novel bifunctional catalyst consisting of nitrogen doped carbon nanotubes (NCNTs) in situ grafted on CoNi-MOF derivative (named CoNi@NC/NCNTs) is controllable synthesized by simple two-steps. Characterization analysis reveal that the interconnected three-dimensional CoNi@NC-NCNTs heterostructure not only atomically dispersed CoNi nanocrystalline, but also autocatalytic grow NCNTs on its surface. The size of CoNi alloy is less than 10 nm, and the crystallization degree of coated graphene carbon layer is extraordinary high. Especially, NCNTs wrapped on CoNi@NC in dihydrodiamine vapour atmosphere form a spatial conductive network, which make the optimized CoNi@NC/NCNTs-400 deliver faster catalytic kinetics toward methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) compared with the CoNi@NC and Co@NC. The peak current density is as high as 58.37 mA cm−2 at the scanning rate is 30 mV s−1 in 0.5 M KOH + 1 M CH3OH solution. Furthermore, the CoNi@NC/NCNTs-400 hybrids display excellent ORR catalytic efficiency in terms of half-wave potential (E1/2 = 0.810 V vs RHE) and high stability. The satisfactory electrocatalytic activity is ascribed to the synergetic effect between CoNi nanoparticles embedded in nitrogen-doped carbon framework and NCNTs, which includes the high conductivity, highly dispersed active sites, optimized electronic configuration and reaction pathways.