Provoking Metallic 1T Phase Conversion of 2H-MoS2 via an Effectual Solvothermal Route for Electrocatalytic Water Reduction in Acid

Recently, the exploration of MoS2-based catalysts especially with a metallic 1T phase has gained immense attention due to their improvised electrocatalytic performance in hydrogen evolution reaction (HER). The dominance in electrical conductivity, hydrophilicity, and density of active sites with the metallic 1T phase over a semiconducting 2H phase is liable for their promoted catalytic performance. The direct formation of MoS2 with an electrocatalytically active 1T phase is hard to attain and demands a proficient method since it is a metastable phase, whereas the 2H phase is a thermodynamically stable and predominantly formed phase in MoS2. On the other hand, in MoS2, the phase conversion from the thermodynamically stable 2H phase to the metastable 1T phase can be feasible with the Li+ ion exfoliation technique. Although it is the foremost employed technique for the industrial-scale formation of 1T-MoS2 at present, the tedious and sedate intercalation/exfoliation process and the usage of explosive Li metal are the prime drawbacks within it. To overcome these issues, in this report, we have proposed a new route for the facile conversion of the 2H phase to the metallic 1T phase in MoS2, which is a solvothermal agitation process with N,N-dimethylformamide (DMF) solvent, where the interlayer expansion due to the intercalation of DMF was observed, which assisted in the attainment of maximal (78.6%) conversion of the 1T phase. Then, the electrocatalytic performance of the prepared 1T-MoS2 catalysts in HER was tested and they showed tremendous activity. To attain a current density of 10 mA cm–2, it demanded 262 mV with a lower Tafel slope value of 53 mV/dec. This humble expedient technique can be valid to the other 2D materials for the facile conversion of the 2H phase to the electrochemically active 1T phase.