Role of Sulfur Vacancies and Undercoordinated Mo Regions in MoS 2 Nanosheets toward the Evolution of Hydrogen

Lei Li (1) , Zhaodan Qin , Lucie Ries (2) , Song Hong (3) , Thierry Michel (4) , Jieun Yang (5) , Chrystelle Salameh (2) , Mikhael Bechelany (2) , Philippe Miele (2) , Daniel Kaplan (6) , Manish Chhowalla (7) , Damien Voiry (2)

1 Northwest Normal University [Lanzhou]
2 IEM - Institut Européen des membranes
3 Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Chemical Resource Engineering, College of Science, Beijing University of Chemical Technology, Beijing
4 L2C - Laboratoire Charles Coulomb
5 Univ Cambridge, Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England
6 FING - Fondation internet nouvelle génération [Paris]
7 RU - Rutgers, The State University of New Jersey [New Brunswick]

Low-dimensional materials have been examined as electrocatalysts for the hydrogen evolution reaction (HER). Among them, two-dimensional transition metal dichalcogenides (2D-TMDs) such as MoS2 have been identified as potential candidates. However, the performance of TMDs toward HER in both acidic and basic media remains inferior to that of noble metals such as Pt and its alloys. This calls for investigating the influence of controlled defect engineering of 2D TMDs on their performance toward hydrogen production. Here, we explored the HER activity from defective multilayered MoS2 over a large range of surface S vacancy concentrations up to 90%. Amorphous MoS2 and 2H MoS2 with ultrarich S vacancies demonstrated the highest HER performance in acid and basic electrolytes, respectively. We also report that the HER performance from multilayered MoS2 can be divided into two domains corresponding to "point defects" at low concentrations of surface S vacancies (Stage 1) and large regions of undercoordinated Mo atoms for high concentrations of surface S vacancies (Stage 2). The highest performance is obtained for Stage 2 in the presence of undercoordinated Mo atoms with a TOF of similar to 2 s(-1) at an overpotential of 160 mV in 0.1 M KOH which compares favorably to the best results in the literature. Overall, our work provides deeper insight on the HER mechanism from defected MoS2 and provides guidance for the development of defect-engineered TMD-based electrocatalysts.

Mots clés: hydrogen evolution reaction; MoS2; sulfur vacancies; undercoordinated Mo; H-2-annealing

Domaines: Chimie

Lei Li, Zhaodan Qin, Lucie Ries, Song Hong, Thierry Michel, et al.. Role of Sulfur Vacancies and Undercoordinated Mo Regions in MoS 2 Nanosheets toward the Evolution of Hydrogen. ACS Nano, 2019, 13 (6), pp.6824-6834. ⟨10.1021/acsnano.9b01583⟩. ⟨hal-02394936⟩