The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

• Published in: Nature materials Vol. 15; no. 9; pp. 1003 - 1009
• Main Authors: Voiry, Damien, Fullon, Raymond, Yang, Jieun, de Carvalho Castro e Silva, Cecilia, Kappera, Rajesh, Bozkurt, Ibrahim, Kaplan, Daniel, Lagos, Maureen J., Batson, Philip E., Gupta, Gautam, Mohite, Aditya D., Dong, Liang, Er, Dequan, Shenoy, Vivek B., Asefa, Tewodros, Chhowalla, Manish
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2016; Nature Publishing Group
• Subjects: 121/137; 140/133; 140/146; 639/301/299/886; 639/301/357/1018; Basal plane; Biomaterials; Catalysis; Catalysts; Catalytic activity; Charge efficiency; Charge injection; Charge transfer; Charge transport; Chemical Sciences; Condensed Matter Physics; Contact resistance; Coupling; Crystals; Electric contacts; Hydrogen evolution reactions; Hydrogen production; Injection; Materials Science; Molybdenum disulfide; Monolayers; Nanosheets; Nanotechnology; Optical and Electronic Materials; Reaction kinetics; Substrates; Sulfur; Tafel slopes
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/nmat4660

The excellent catalytic activity of metallic MoS 2 edges for the hydrogen evolution reaction (HER) has led to substantial efforts towards increasing the edge concentration. The 2H basal plane is less active for the HER because it is less conducting and therefore possesses less efficient charge transfer kinetics. Here we show that the activity of the 2H basal planes of monolayer MoS 2 nanosheets can be made comparable to state-of-the-art catalytic properties of metallic edges and the 1T phase by improving the electrical coupling between the substrate and the catalyst so that electron injection from the electrode and transport to the catalyst active site is facilitated. Phase-engineered low-resistance contacts on monolayer 2H-phase MoS 2 basal plane lead to higher efficiency of charge injection in the nanosheets so that its intrinsic activity towards the HER can be measured. We demonstrate that onset potentials and Tafel slopes of ∼−0.1 V and ∼50 mV per decade can be achieved from 2H-phase catalysts where only the basal plane is exposed. We show that efficient charge injection and the presence of naturally occurring sulfur vacancies are responsible for the observed increase in catalytic activity of the 2H basal plane. Our results provide new insights into the role of contact resistance and charge transport on the performance of two-dimensional MoS 2 nanosheet catalysts for the HER. Increasing the edge concentration of metallic MoS 2 nanosheets will improve their electrocatalytic performance for hydrogen evolution. The activity of MoS 2 can now be enhanced by facilitating electron injection from the electrode to the catalyst.