Spontaneous doping of the basal plane of MoS2 single-layers through oxygen substitution under ambient conditions

János Pető; Tamás Ollár; Péter Vancsó; Zakhar I. Popov; Gábor Zsolt Magda; Gergely Dobrik; Chanyong Hwang; Pavel B. Sorokin; Levente Tapasztó

doi:10.1038/s41557-018-0136-2

arXiv · 1904.01411

Spontaneous doping of the basal plane of MoS2 single-layers through oxygen substitution under ambient conditions

János Pető·Tamás Ollár·Péter Vancsó·Zakhar I. Popov·Gábor Zsolt Magda·Gergely Dobrik·Chanyong Hwang·Pavel B. Sorokin·Levente Tapasztó

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Abstract

The chemical inertness of the defect-free basal plane confers environmental stability to MoS2 single-layers, but it also limits their chemical versatility and catalytic activity. The stability of the pristine MoS2 basal plane against oxidation under ambient conditions is a widely accepted assumption in the interpretation of various studies and applications. However, single-atom level structural investigations reported here reveal that oxygen atoms spontaneously incorporate into the basal plane of MoS2 single layers during ambient exposure. Our scanning tunneling microscopy investigations reveal a slow oxygen substitution reaction, upon which individual sulfur atoms are one by one replaced by oxygen, giving rise to solid solution type 2D MoS2-xOx crystals. O substitution sites present all over the basal plane act as single-atomic active reaction centers, substantially increasing the catalytic activity of the entire MoS2 basal plane for the electrochemical H2 evolution reaction.

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János Pető, Tamás Ollár, Péter Vancsó, Zakhar I. Popov, Gábor Zsolt Magda, Gergely Dobrik, Chanyong Hwang, Pavel B. Sorokin, Levente Tapasztó. 2019-04-02. Spontaneous doping of the basal plane of MoS2 single-layers through oxygen substitution under ambient conditions. https://doi.org/10.1038/s41557-018-0136-2

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