Hydrazine Hydrate Intercalated 1t-Dominant Mos2 with Long-Term Ambient Stability for Efficient Electrocatalytic Applications

Metallic 1T-phase MoS 2 usually exhibits superior hydrogen evolution reaction (HER) performance than natural 2H phase MoS 2 owing to its higher electrical conductivity and increased abundance of active sites. However, the reported 1T-MoS 2 catalysts typically suffer from extreme instability, resulting in quick phase transformation at ambient conditions. Herein, we present a facile yet effective approach to engineering the phase of MoS 2 through introducing intercalated hydrazine. Surprisingly, the as-synthesized 1T-dominant MoS 2 sample demonstrates excellent ambient stability without significant degradation for 3 months. Additionally, the 1T-dominant MoS 2 exhibits superior electrical conductivity (~700 times higher than 2H-MoS 2 ) and improved electrochemical catalytic performance (current density ~12 times larger than 2H-MoS 2 at overpotential 300 mV vs. RHE). Through experimental characterizations and density functional theory (DFT) calculations, we conclude that the stabilization of the metallic phase can be attributed to the electron donation from hydrazine molecules to the adjacent Mo atoms. The phase control strategy in this work may be applied to develop highly efficient and stable 2D electrocatalysts