Abstract
Two-dimensional(2D)metallic 1T-CoTe2 has attracted considerable attention due to its fascinating physical properties and promising applications in elec-tronics and catalysis.However,the production of high-quality 2D 1T-CoTe2 still remains challenging.Herein,we demonstrate a methodology to realize the facile synthesis of ultrathin,high-quality CoTe2 flakes with a thickness down to 2.3 nm on mica substrates by an ambient-pressure chemical vapor deposition(CVD)technique.The atomic arrangement is verified by scanning transmission electron microscopy.The theoretical calculations uncover the metallic characteristic of 1T-CoTe2 in the 2D limit.Remarkably,the CVD-derived 2D metallic CoTe2 flakes for the hydrogen evolution reaction(HER)catalyst exhibit admirable performance,such as an overpotential of 186 mV at 10 mA.cm-2,aTafel slope of 78 mV·dec-1,an exchange current density of 69 μA.cm-2,and negligible performance degradation after 1000 cycles.These results establish novel approaches for the synthesis and HER application of 2D metallic 1T-CoTe2.
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