In-Situ Pt-Decorated, Direct Growth of Mixed Phase 2H/1T–MoSe₂ on Carbon Paper for Enhanced Hydrogen Evolution Reaction

Metal dichalcogenide-based 2D materials, gained considerable attention recently as a hydrogen evolution reaction (HER) electrocatalyst. In this work, we synthesized MoSe₂-based electrocatalyst via hydrothermal route with varying phase contents (1T/2H) and respective HER performances were evaluated under the acidic media (0.5 M H₂SO₄), where best HER performance was obtained from the sample consisting of mixed 1T/2H phases, which was directly grown on a carbon paper (167 mV at 10 mA cm⁻²) Furthermore, HER performance of electrocatalyst was further improved by in-situ electrodeposition of Pt nanoparticles (0.15 wt%) on the MoSe₂ surface, which lead to significant enhancement in the HER performances (133 mV at 10 mA cm⁻²). Finally, we conducted density functional theory calculations to reveal the origin of such enhanced performances when the mixed 1T/2H phases were present, where phase boundary region (1T/2H heterojunction) act as a low energy pathway for H₂ adsorption and desorption via electron accumulation effect. Moreover, presence of the Pt nanoparticles tunes the electronic states of the MoSe₂ based catalyst, resulting in the enhanced HER activity at heterointerface of 1T/2H MoSe₂ while facilitating the hydrogen adsorption and desorption process providing a low energy pathway for HER. These results provide new insight on atomic level understanding of the MoSe₂ based catalyst for HER application.