Nb₄C₃T_x (MXene) as a new stable catalyst for the hydrogen evolution reaction

This article reports, for the first time, the application of Nb₄C₃T_x in the MXene series satisfying the formula of M₄C₃T_x in the field of hydrogen evolution reaction (HER). New etching parameters are proposed to obtain Nb₄C₃T_x with the largest c-lattice constant (3.165 nm) to date. Notably, Nb₄C₃T_x shows higher catalytic activity under the alkaline condition. Consequently, Nb₄C₃T_x has an overpotential of 398 mV at a current density of 10 mA cm⁻², which is considerably less than that of other reported MXenes. Moreover, Nb₄C₃T_x has superior cycling performance and long-term stability in both acidic and alkaline environments. After 1000 cycles of CV, the overpotential of Nb₄C₃T_x clearly decreased by approximately 30 mV, and the current density significantly increased after the timing current test up to 50 h. This work demonstrates the excellent electrochemical performance that Nb₄C₃T_x can provide to benefit broad application prospects in energy fields.