Facilitating the Hydrogen Evolution Reaction on Basal-Plane S Sites on MoS2@Ni3S2 by Dual Ti and N Plasma Treatment

Atomic engineering of the basal plane active sites in MoS2 holds great promise to boost the electrocatalytic activity for hydrogen evolution reactions (HER), yet the performance optimization and mechanism exploration are still not satisfactory. Herein, we proposed a dual-plasma engineering strategy to implant Ti and N heteroatoms into the basal plane of MoS2 supported by Ni3S2 nanorods on nickel foam (MSNF) for efficient electrocatalysis of HER. Owing to the low formation energy of Ti dopants in MoS2 and the extra charge carriers introduced by N dopants, the optimally codoped samples N1.0@Ti500-MSNF demonstrate significant morphology changes from nanorods to urchin-like nanospheres with the surface active areas increased by seven-fold, as well as enhanced electrical conductivity in comparison with the nondoped counterparts. The HER performance of N1.0@Ti500-MSNF is comparable with the Pt-based catalyst: overpotential of 26 mV at 20 mA cm–2, Tafel slope of 35.6 mV dec–1, and long-term stability over 50 h. First-principles calculation reveals that N doping accelerates the dissociation of water molecules while Ti doping activates the adjacent S sites for hydrogen adsorption by lowering the Gibbs free energy, resulting in excellent HER activity. This work thus provides an effective strategy for basal plane engineering of MoS2 heterostructures toward high-performance HER and sustainable energy supply at reasonable costs.