One-pot hydrothermal approach towards 2D/2D heterostructure based on 1 T MoS2 chemically bonding with GO for extremely high electrocatalytic performance

Molybdenum disulfide (MoS2) has become a promising low-cost alternative to Pt catalyst for electrochemical Hydrogen evolution reactions (HER). However, the poor conductivity and limited active sites of thermody-namically stable 2H-Phase MoS2 hinder its catalytic performance. Utilizing phase engineering to convert 2H MoS2 to metallic 1 T MoS2 is an effective strategy to improve the catalytic activity of MoS2. The commonly used synthetic and phase engineering methods such as electrochemical exfoliation involve using a complicated synthesis route or under strict experimental conditions or both. Herein, we develop a one-pot hydrothermal method to in-situ synthesize a 2D (1 T MoS2)/2D (GO) heterostructure with a face-to-face contact between the ultrathin MoS2 (few layers) and Graphene oxide (GO). The content of 1 T MoS2 in the prepared 1 T MoS2/GO reaches as high as 76.7%. When used as a catalyst, 1 T MoS2/GO exhibited an outstanding HER performance, with a small overpotential of 209 mV at a cathode current density of 10 mA cm(-2), and an extremely low Tafel slope of 45.5 mV Dec(-1), which is very close to that of Pt/C (40.0 mV Dec(-1)). Moreover, it demonstrated an excellent stability after a storage of 212 days in air. The high electrocatalytic performance could be attributed to the high 1 T-phase content in the MoS2, as the 1 T phase provides numerous active sites and improves the electronic conductivity of the catalyst. Strong interactions between 1 T MoS2 and GO substrate stabilizes the structure of the 1 T MoS2 and allows rapid charge transfer kinetics. This work proposes a facile and effective strategy for the design and synthesis of transition metal chalcogenides with high HER performance.