title: Engineering the Edges of MoS2(WS2) Crystals for Direct Exfoliation into Monolayers in Polar Micromolecular Solvents.
abstract: Synthesizing transition metal dichalcogenide (TMDC) monolayers through the liquid exfoliation of bulk crystals in low boiling point polar micromolecular solvents, such as water, is paramount for their practical application. However, the resulting hydrodynamic forces only appear on the crystal edges due to the mismatch in surface tension between the polar micromolecular solvents and the bulk crystals and are insufficient to overcome the strong van der Waals attraction between adjacent microscale layers. Herein, we present the novel strategy of engineering the lateral size of TMDC (MoS2and WS2) crystals in the nanoscale to increase the fraction of edges, leading to their direct and ready exfoliation in polar micromolecular solvents, even in pure water, to produce monolayer MoS2and WS2nanosheets in high yield. To examine one of their important applications, their catalytic hydrogen evolution activities were evaluated when used as cocatalysts with a photoharvester semiconductor (cadmium sulfide, CdS) in a reaction driven by solar energy. These exfoliated MoS2(WS2) monolayers exhibited superior cocatalytic performance in the photocatalytic hydrogen evolution reaction (HER). Notably, the cocatalytic performance of monolayer WS2nanosheets is even higher than that of platinum (Pt), which is a state-of-the-art catalyst for catalytic hydrogen evolution. This work elucidates the importance of decreasing the lateral size of layered crystals to significantly enhance their exfoliability, providing a new strategy for the large-scale preparation of nanoscale TMDC monolayers by liquid exfoliation.
authors: Graduate School of Chemical Science and Engineering, Hokkaido University , Sapporo 060-0814, Japan.|Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Xiao
authors: X
authors: Hai
authors: Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Kun
authors: K
authors: Chang
authors: Graduate School of Chemical Science and Engineering, Hokkaido University , Sapporo 060-0814, Japan.|Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Hong
authors: H
authors: Pang
authors: Graduate School of Chemical Science and Engineering, Hokkaido University , Sapporo 060-0814, Japan.|Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Mu
authors: M
authors: Li
authors: Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Peng
authors: P
authors: Li
authors: Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Huimin
authors: H
authors: Liu
authors: Graduate School of Chemical Science and Engineering, Hokkaido University , Sapporo 060-0814, Japan.|Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors: Li
authors: L
authors: Shi
authors: Graduate School of Chemical Science and Engineering, Hokkaido University , Sapporo 060-0814, Japan.|Photocatalytic Materials Group, International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science , 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.|TU-NIMS Joint Research Center, School of Materials Science and Engineering, Tianjin University , 92 Weijin road, Tianjin 300072, P. R. China.|Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072, P. R. China.
authors: Jinhua
authors: J
authors: Ye