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Volume 91 Issue 26 | p. 19 | Concentrates
Issue Date: July 1, 2013

Metallic Molybdenum Disulfide Nanosheets Enhance Hydrogen Evolution

Material could make final step of water splitting less expensive
Department: Science & Technology
News Channels: JACS In C&EN, Materials SCENE, Nano SCENE
Keywords: molybdenum disulfide, MoS2, hydrogen evolution reaction, water splitting, electrocatalysis
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A simple chemical method exfoliates MoS2, as seen in this SEM image, and boosts its catalytic activity.
Credit: J. Am. Chem. Soc.
09126-scicon-MoS2exfoliatedcxd
 
A simple chemical method exfoliates MoS2, as seen in this SEM image, and boosts its catalytic activity.
Credit: J. Am. Chem. Soc.

Hydrogen’s appeal as an environmentally friendly fuel and energy carrier is heightened by the tantalizing possibility of obtaining the lightweight gas by splitting water. The final step in that process, the hydrogen evolution reaction (HER), reduces and combines hydrogen ions to form H2. Platinum is a top-notch HER catalyst, but it is expensive. The search for low-cost alternatives recently turned up MoS2, an unexpected but promising candidate. Now, chemists at the University of Wisconsin, Madison, report a simple chemical process that transforms MoS2 from a semiconducting phase to a metallic one and significantly enhances its performance as an HER catalyst (J. Am. Chem. Soc. 2013, DOI: 10.1021/ja404523s). Mark A. Lukowski, Song Jin, and coworkers used standard chemical vapor deposition methods to grow semiconducting MoS2 on graphite. By treating the product with n-butyllithium and water, they produced exfoliated metallic MoS2 nanosheets. Electrocatalysis and other tests show that, compared with the starting material, the nanosheets expose a higher density of HER active sites, mediate faster electrode kinetics, and enhance electronic conductivity. This simple method of altering nanostructures may be useful in modifying other layered materials to enhance their properties, the team suggests.

 
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