From 1T to 2H: Engineering Mo S 2 phases through tunable hydrothermal routes

Molybdenum disulfide (Mo S 2 ) has attracted a lot of attention in recent years due to its unique structural polymorphism, primarily the semiconducting 2H phase (2H-Mo S 2 ) and the metallic 1T phase. The 2H phase is widely employed in optoelectronics, catalysis, and energy storage devices due to its inherent bandgap, while the metallic 1T phase (1T-Mo S 2 ) exhibits excellent electrical conductivity and catalytic activity, indicating its potential for use in supercapacitors and hydrogen evolution processes (HER). The ability to tune the phase composition of Mo S 2 is critical for optimizing its performance in such diverse applications. In this study, we report the controlled synthesis of Mo S 2 phases using a single hydrothermal process by systematically varying synthesis parameters — such as precursor concentration, reaction time, temperature, and pH — we effectively tuned the energy kinetics governing phase formation. The optimized parameters used for selective synthesis of 2H-Mo S 2 , 1T-Mo S 2 , and mixed-phase compositions. Detailed characterization of the flower like Mo S 2 Microspheres using X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM) confirmed the phase purity and morphological features of the synthesized materials. Our work provides a scalable and reproducible approach for phase-engineering of Mo S 2 , enabling its tailored design for targeted applications in energy storage, catalysis, and nanoelectronics. • Controlled hydrothermal synthesis of 2H, 1T, and mixed-phase MoS 2 nanostructures. • Phase engineering achieved via tuning reaction temperature and precursor chemistry. • Hierarchical flower-like MoS 2 microspheres confirmed by XRD, Raman, and TEM. • 1T to 2H phase transformation explained using thermodynamic and kinetic models. • Scalable and reproducible method enables tailored MoS 2 design for energy applications.