Boosting the electrocatalytic overall water splitting performance by synergistically coupling N-doped delaminated niobium carbide MXene and N-doped graphitic carbon

A robust trifunctional electrocatalyst based on N-doped delaminated niobium carbide (N-Nb4C3Tx) nanosheets encapsulated by N-doped graphitic carbon (NGC) (abbreviated as N-Nb4C3Tx/NGC) is synthesized, which exhibits a low overpotentials of 96 and 291 mV at 10 mA cm(-2) for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The superior electrocatalytic performance can be attributed to the synergetic effect of the highly conductive N-Nb4C3Tx and doping of the high-content NGC. The introduction of N species plays an important roles of generating graphitic N-doped carbon species and anchoring N in the carbon matrix, which further boost the electrocatalytic activity. The structure properties and nitrogen content of MXene were regulated by the mass ratio of Nb4C3Tx to hexamethylenetetramine (HMTA). These results indicate that the method of synergistically coupling N-Nb4C3Tx and NGC can boost the HER, OER, and overall water splitting performance, providing a new strategy for the development of economical and efficient MXene based electrocatalysts.