In the face of rising energy demand and depleting energy resources, energy sustainability has proven to be a formidable environmental and economic challenge, and the search for environmentally friendly energy sources is exigent. To this end, much research has been focused on improving the efficiency of the hydrogen evolution reaction (HER), which generates hydrogen gas, a renewable source of energy carrier. To resolve the steep cost issue of employing Pt, transition metal dichalcogenides (TMDs) have been proposed as emerging HER electrocatalysts, among other electrochemical applications. As the exfoliated TMD exhibits properties distinct from the bulk material, it is prudent to investigate the exfoliation procedure with specific regard to the employed intercalant. Here, we prepared exfoliated MoS2, MoSe2, WS2, and WSe2 from their bulk counterparts using aromatic intercalants, i.e. phenyllithium, sodium naphthalenide, and sodium anthracenide, and characterized them using scanning electron microscopy (SEM), Raman spectroscopy, methylene blue surface area measurement, and X-ray photoelectron spectroscopy (XPS). Voltammetric investigations were performed to examine the effects of different intercalants on the electrochemical sensing capability and HER catalytic efficiency of these TMDs. Our findings establish both advantageous and detrimental impacts of altering the intercalant on the electrochemical performances of TMDs upon exfoliation, depending on the intended application of their electrochemistry.
Bibliographical noteFunding Information:
M.P. was supported from Tier 2 grant from Ministry of Education, Singapore. Z.S. and J.L. were supported by specific university research (MSMT No. 20-SVV/2016) and by Czech Science Foundation (GACR No. 16-05167S).
© 2016 American Chemical Society.
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