Chemical vapor deposition of uniform bilayer PtS 2 flakes for electrocatalytic hydrogen evolution.

Two-dimensional (2D) 1T-PtS 2 has been drawing considerable attention due to its highly layer-dependent bandgap, high carrier mobility, superior air stability, etc. However, the growth of 2D PtS 2 with uniform thickness and controllable shape remains an immense challenge. Herein, the uniform bilayer (2L) 1T-PtS 2 single crystals are controllably grown on mica using chemical vapor deposition for the first time. The variable morphology from triangular to hexagonal can be obtained by regulating growth temperature. Significantly, the 2L PtS 2 flakes show a good electrocatalytic hydrogen evolution reaction (HER) property with an overpotential of 184 mV at 10 mA cm -2 , Tafel slope of 81 mV dec -1 , exchange current density of 43 μA cm -2 , and outstanding stability. This work manifests that 2D PtS 2 is a promising candidate for HER applications.