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-Nb ₄C ₃T _x) nanosheets encapsulated by N-doped graphitic carbon (NGC) (abbreviated as N-Nb ₄C ₃T _x/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-Nb ₄C ₃T _x 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 Nb ₄C ₃T _x to hexamethylenetetramine (HMTA). These results indicate that the method of synergistically coupling N-Nb ₄C ₃T _x 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.