861
Exfoliated Vanadium Dichalcogenides (VS2, VSe2, VTe2) By Lithium Intercalation Exhibit Dramatically Different Properties from Their Bulk Counterparts

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)
Y. Wang (Nanyang Technological University), Z. Sofer, J. Luxa (Institute of Chemical Technology Prague), and M. Pumera (Nanyang Technological University)
Layered transition metal dichalcogenides (TMDs) have been attracting great interest due to their excellent electrical, optical, and electrochemical properties they exhibit when exfoliated down to mono- or a few-layer material. Driven by the unique properties, numerous methods have been developed to isolate few-layered TMDs. In this study, lithium intercalation route which is initially established for MoS2 and WS2 has been adopted to exfoliate the vanadium dichalcogenides (VS2, VSe2, and VTe2). Following the inherent electrochemical properties of these bulk and exfoliated vanadium dichalcogenides were studied along with their potential as electrocatalysts towards hydrogen evolution reaction (HER). This lithium intercalation method leads to the different degree of exfoliation following the VS2 > VSe2 > VTe2 order. Besides, upon exfoliation to single/few layer VX2 become partly converted to nonstoichiometric vanadium oxide and lithium vanadates, which is strikingly different when compared to group 6 TMDs, such as MoX2 and WX2. Inherent electrochemical results indicate that both bulk and exfoliated VS2, VSe2, and VTe2 possess inherent electrochemical activity, which can limit their application for electrocatalysts and electrode materials. HER performance study of bulk and exfoliated vanadium dichalcogenides shows that the presence of vanadium oxides and lithium vanadates formed during the exfoliation process can highly influence the HER performance.