Synthesis of Air‐stable 1T Phase of Molybdenum Disulfide for Efficient Electrocatalytic Hydrogen Evolution

다국어 초록 (Multilingual Abstract)

Phase engineering of MoS2 from the thermodynamically stable 2H phase to the metastable 1T phase has been demonstrated as an effective way to enhance the electrocatalytic activity for hydrogen evolution reaction (HER). However, the development of highly stable and efficient 1T‐MoS2‐based electrocatalysts toward HER still remains a great challenge. Herein, a facile hydrothermal strategy was introduced for the preparation of stable 1T‐MoS2 via a reduced graphene oxide (RGO)‐assisted process. The optimal catalyst of MoS2/RGO can keep highly stable in air over 90 days without significant activity fading due to Mo−O interactions, which effectively prevent the transformation of 1T phase back to 2H. The catalyst affords superior HER catalytic activity with a low overpotential of 213 mV versus reversible hydrogen electrode (RHE) at a current density of −10 mA cm−2, a small Tafel slope of 43 mV dec−1, a high exchange current density of 0.83 mA cm−2, and excellent durability, which outperforms its corresponding 2H counterpart. The enhanced electrocatalytic activity of the optimal MoS2/RGO sample is associated with the RGO, which can not only facilitate charge transfer along MoS2 nanosheets but also stabilize the 1T‐MoS2 with a high exposure of active sites for HER. This work paves a new pathway for designing highly efficient MoS2‐based electrocatalysts through phase engineering.
The as‐synthesized 1T‐MoS2/RGO nanocomposites exhibit excellent stability in air with no obvious decay of hydrogen evolution activities over 90 days. This mainly attributed to reduced graphene oxide (RGO) which can not only facilitate charge transfer but also stabilize the 1T‐MoS2 with a high exposure of active sites. More importantly, RGO can effectively prevent transformation of MoS2 from 1T phase to 2H phase due to Mo−O interactions.