Efficient tuning the electronic structure of N-doped Ti-based MXene to enhance hydrogen evolution reaction

The exploration of low cost electrocatalyst with comparable catalytic activity and kinetics to the expensive noble metal catalysts for hydrogen evolution reaction (HER) is still the most urgent challenge. Herein, a facile strategy to synthesize Ti₃C₂T_x MXene by ultrasonication with controlled N-doping is reported. The surface modification of MXene can be achieved by the formation of TiN chemical bonds at an optimized ultrasonic temperature, which will further enhance the HER activity. Specifically, at the ultrasonic temperature of 35 °C, the N-doped MXene (N-MXene-35) exhibits the highest concentration of TiN bond, delivering an extraordinary HER activity with an overpotential of 162 mV (vs. the reversible hydrogen electrode, RHE) at the current density of 10 mA cm^-2 in acid media, which is 3.5 times lower than that of the pristine MXene (578 mV vs. RHE). As expected, the obtained N-MXene-35 affords the best HER electrocatalytic performance among the MXene or N-doped MXene electrode as so far reported.