3. Conclusions
In this work, we successfully prepared self-standing 1T/2H mixed phases of MoSe2 on a carbon paper using a direct growth approach via hydrothermal synthesis method, where post in-situ Pt decoration was carried out by electrodeposition method. The electrocatalyst (Pt decorated1T/2H mixed phase of MoSe2) prepared by this simple two step approach exhibit high HER activity (133 mV at 10 mA/cm2) under the acidic medium (0.5 M H2SO4). The direct growth of 1T/2H mixed phase MoSe2 on a carbon paper contributes to the lower Rct with reduction in the overpotential by 10 mV at a current density of 10 mA/cm2 compared to the electrocatalyst prepared by conventional (electrocatalyst + binder) approach. Moreover, low concentration (0.15 wt%) decoration of Pt contributes to significant enhancement in the HER activity with further reduction in Rct compared to the pristine 1T/2H MoSe2 electrocatalyst without the Pt deposition. Such results are well supported by the DFT calculation and provides insight on enhanced HER activity at the phase boundary region in MoSe2 compared to the 1T or 2H alone regions due to the electron accumulation at the heterointerface, while Pt clusters interacts with Se site in MoSe2 while perturbing the electronic states of MoSe2, which further improves the HER activity and confirmed through ΔGH and Ed analysis, highlighting a origin of phase dependent HER performances in MoSe2 based electrocatalyst in the presence of a dopant, which will pave a way for developing advanced metal dichalcogenide 2D material based electrocatalyst in future.