title: Layer-controllable WS2-reduced graphene oxide hybrid nanosheets with high electrocatalytic activity for hydrogen evolution.
abstract: In this study, an efficient poly(vinylpyrrolidone) (PVP)-assisted hydrothermal method for the in situ growth of WS2 nanosheets with layer-controllability on reduced graphene oxide (rGO) is reported. The number of layers (from a monolayer to ∼25 layers) of the exfoliated WS2 can be accurately controlled by adjusting the amount of PVP. The layer structure and the morphology of the as-prepared hybrids are confirmed by field emission scanning electron microscopy and high-resolution transmission microscopy. The X-ray diffraction, Raman, and X-ray photoemission spectroscopy of the obtained WS2-rGO hybrid nanosheets indicate highly crystallized structures, a clear Raman shift and a stoichiometry, which is dependent on the number of layers. Furthermore, these highly active and durable catalysts exhibit an electrocatalytic current density of 10 mA cm(-2) at a small hydrogen evolution reaction (HER) overpotential (-170 mV) and a Tafel slope of 52 mV dec(-1) with an excellent electrocatalytic stability (after 6 months storage).
authors.affiliation: Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023, PR China. lxahbmy@126.com.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Lianhui
authors.initials: L
authors.lastname: Wang
authors.forename: Xing'ao
authors.initials: X
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Huang