Ru doping induces phase transition and in-plane S-site electronic modulation in ternary MoS heterostructures to enhance hydrogen evolution in water/seawater.

Optimizing the performance of in-plane S atoms of MoS is crucial to extend the breadth of application of MoS. Herein, using a simple hydrothermal method, we prepared a novel electrocatalyst of Ru incorporated into trinary-MoS (Ru-MoS) nanoflowers. Ru doping could promote preferential transition from the semiconducting (2H) phase to the metallic (1T and 1T') phase in the basal plane. Density functional theory (DFT) calculations confirmed that Ru incorporated into MoS could optimize the electronic structure, improve the conductivity and optimize H* adsorption in interfacial S sites of trinary-MoS, and facilitate the catalytic hydrogen evolution activity. Moreover, in-plane S sites on the Ru doping 2H/1T' heterostructure have been shown to be highly active sites for trinary-MoS. Benefiting from the good conductivity and activated interfacial S sites in trinary-MoS, the prepared Ru-MoS exhibited superior electrocatalytic activity at 10 mA cm and only required overpotentials of 89 mV and 112 mV in alkaline solution and alkaline seawater, respectively. This work provides a fresh insight into the design of highly-efficient trinary-MoS electrocatalysts.