463880 Microwave-Assisted Fast Rout to Achieve 1T to 2H Phase Reversion of MoS2 in Solution: Processable Dispersions of 2H MoS2 Nanosheets and 2H-MoS2/Pt Composite

Monday, November 14, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Danyun Xu, Yuanzhi Zhu, Wenchao Peng, Guoliang Zhang and Xiaobin Fan, School of Chemical Engineering & Technology, Tianjin University, Tianjin, China

Exfoliated molybdenum disulfide (MoS2) with 2H phase and semiconductor properties has unique properties and potential applications in a wide range of fields. However, the chemically exfoliated MoS2 nanosheets are metallic 1T phase. Many methods have been developed to achieve 1T to 2H reversion. For example, Eda G. and co-workers demonstrated the successful phase reversion of MoS2 nanosheets by annealing at temperature of 300 °C for 1 hour with a heating rate of 5 °C/min. We also revealed that this phase reversion could be achieved by NIR radiation with a commercial DVD optical drive in a previous study.  Different from these studies limited to nanosheets deposited on solid substrates, Stanley S. Chou and co-workers have recently get processable MoS2 and WS2 dispersion with 2H phase by refluxing in inert high boiling point solvents like octadecene for 4 hours with a heating rate of ≈ 10 °C/min. However, searching for new strategies to achieve the phase reversion, especially a fast rout to get processable 2H-MoS2 nanosheets and its nanocomposites remains an urgent task. This study reports a simple, fast and efficient microwave strategy to achieve 1T to 2H phase conversion of MoS2. On the basis of the phase transformation, we also successfully realized the in-situ deposition of Pt NPs on the 2H-MoS2 nanosheets. The chemically exfoliated MoS2 nanosheets were transferred from water into the inert nonpolar solvent, o-dichlorobenzene (ODCB) according to the study by Stanley S. Chou and co-workers. Then the samples were treated by microwave irradiation. We also achieved the phase reversion and 2H-MoS2/Pt nanocomposites with introducing the metal precursor. The microwave strategy described here should be easily adaptable to achieve the phase change of other exfoliated TMDs and to prepare other novel nanocomposite on a bulk scale.

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