Activating transition metal dichalcogenide monolayers as efficient electrocatalysts for the oxygen reduction reaction via single atom doping

Abstract

Recent studies on 2D transition-metal-dichalcogenides (TMDs) for electrocatalytic applications have mainly concentrated on MoS₂, while the catalytic properties of the majority of other TMDs remain undiscovered. This work reveals the activity of sulfur-based IVB–BVII TMDs in different phase structures for the oxygen reduction reaction (ORR). The pristine TMDs are inactive for the ORR. Adatom doping with transition metals and non-metal substitutional doping are efficient strategies to modify TMDs. Particularly, Ni or Co doped 1T-TiS₂, 2H-TiS₂, 1T-ZrS₂, 1T-TaS₂, 1T-NbS₂ and 2H-TaS₂ act as feasible ORR electrocatalysts with overpotential (0.32–0.55 V) comparable to that of state-of-the-art Pt-based electrocatalysts. However, 2H-WS₂, 2H-TaS₂, 2H-TiS₂ and 1T′-WS₂ can be effectively activated by N doping with an overpotential of 0.3–0.75 V. Our predictions show an effective way to modify the ORR activity of TMDs by single atom doping, which would be helpful to provoke future experimental interest of the ORR in these systems.