Second diffusion of Co particles during MoS2 incorporated in N-doped carbon nanotubes towards superior electrochemical activity

Abstract

Transition metal endowed carbon nanotubes are widely used in electrochemical catalytic reactions. The distribution of transition metal affected their performance. Herein, Co particles were firstly embedded in N-doped carbon nanotubes. During the deposition of molybdenum disulfide (MoS2), the size of Co particles was drastically decreased. This phenomenon is ascribed to the reaction between Co and S2− ions. Finally, MoS2/Co/N-doped carbon heterostructures formed. Such heterostructures exhibited excellent activity for electrocatalytic water splitting. It effectively improves the electrocatalytic hydrogen evolution ability of the carbon nanotubes with an over potential of 468 mV at 50 mA/cm2 current density. In addition, the formation mechanism of the Mo–N–C interface coupling structure has also been proposed. This unique structure facilitates further design research on carbon materials. It is worth mentioning that nitrogen-doped bamboo-like carbon nanotubes have good oxygen reduction reaction activity, and the half-wave potential can reach 792 mV, the onset potential is 931 mV, and the ultimate diffusion current density is 5.3 mV/cm2, which is close to the expensive commercial Pt/C electrodes.