Tunable nitrogen-doped delaminated 2D MXene obtained by NH3/Ar plasma treatment as highly efficient hydrogen and oxygen evolution reaction electrocatalyst

Constructing two-dimensional MXene surface defects can greatly improve electrocatalytic performance. Herein, a one-step NH3/Ar plasma treatment method was used to obtain few-layered and nitrogen-doped Ti3C2Tx MXene. The structural properties and nitrogen content of MXene were adjusted by controlling the volume ratio of NH3 and Ar in the plasma gas. When the volume ratio of ammonia-to-argon was 6:1, the obtained Ti3C2Tx-N6 had the largest C lattice parameter (13.53 Å), the highest nitrogen content (1.57 wt%), and the lowest HER overpotential of 119.17 mV. The XPS results and DFT calculations showed that Ti3C2Tx-N6 introduced the most surface-adsorbed N, which reduced the energy barrier of electrocatalytic reactions of MXene.