All The Catalytic Active Sites of MoS2 for Hydrogen Evolution.
Journal Article (Journal Article)
MoS2 presents a promising low-cost catalyst for the hydrogen evolution reaction (HER), but the understanding about its active sites has remained limited. Here we present an unambiguous study of the catalytic activities of all possible reaction sites of MoS2 , including edge sites, sulfur vacancies, and grain boundaries. We demonstrate that, in addition to the well-known catalytically active edge sites, sulfur vacancies provide another major active site for the HER, while the catalytic activity of grain boundaries is much weaker. The intrinsic turnover frequencies (Tafel slopes) of the edge sites, sulfur vacancies, and grain boundaries are estimated to be 7.5 s-1 (65-75 mV/dec), 3.2 s-1 (65-85 mV/dec), and 0.1 s-1 (120-160 mV/dec), respectively. We also demonstrate that the catalytic activity of sulfur vacancies strongly depends on the density of the vacancies and the local crystalline structure in proximity to the vacancies. Unlike edge sites, whose catalytic activity linearly depends on the length, sulfur vacancies show optimal catalytic activities when the vacancy density is in the range of 7-10%, and the number of sulfur vacancies in high crystalline quality MoS2 is higher than that in low crystalline quality MoS2 , which may be related with the proximity of different local crystalline structures to the vacancies.
Full Text
Duke Authors
Cited Authors
- Li, G; Zhang, D; Qiao, Q; Yu, Y; Peterson, D; Zafar, A; Kumar, R; Curtarolo, S; Hunte, F; Shannon, S; Zhu, Y; Yang, W; Cao, L
Published Date
- December 15, 2016
Published In
Volume / Issue
- 138 / 51
Start / End Page
- 16632 - 16638
PubMed ID
- 27977198
Electronic International Standard Serial Number (EISSN)
- 1520-5126
International Standard Serial Number (ISSN)
- 0002-7863
Digital Object Identifier (DOI)
- 10.1021/jacs.6b05940
Language
- eng