Scalable production of intrinsic WX2(X = S, Se, Te) quantum sheets for efficient hydrogen evolution electrocatalysis.

Mass production of transition-metal dichalcogenides has attracted much attention to replace platinum-based catalysts for the hydrogen evolution reaction (HER). Herein, we demonstrate a general strategy for the scalable production of the intrinsic tungsten dichalcogenide (WX2(X = S, Se, Te)) quantum sheets (QSs) by an all-physical top-down method. The method combines silica-assisted ball-milling and sonication-assisted solvent exfoliation and thus enables production of WS2QSs, WSe2QSs, and WTe2QSs in exceedingly high yields of 28.2, 21.3, 19.9 wt%, respectively. The WX2QSs are confirmed as intrinsic and defect-free, which could be determinative to their improved HER performance. The overpotentials of 285, 331, 435 mV at the current density of 10 mA cm-2and Tafel slopes of 116, 78, 162 mV dec-1in acidic media, as well as charge transfer resistance values of 171, 242, 1973 Ω, are derived for WS2QSs, WSe2QSs, and WTe2QSs, respectively, which are much better than those of bulk materials. The WX2QSs exhibit high stability during the electrocatalysis as well. This work offers a powerful approach for fabrication of intrinsic QSs as efficient and robust electrocatalysts.