Unlocking the potential of MoS2 for efficient hydrogen generation by controlling hydrothermal conditions

초록

Introducing foreign elements, clusters, and nanoparticles to two-dimensional MoS2 is the usual approach to getting highly active electrocatalysts for the hydrogen evolution reaction (HER) without or with a minimum amount of precious metals. Yet, the catalytic properties of bare MoS2 can still optimize the final performance of electrocatalysts. In the present work, it is unraveled how the structure of MoS2 can be systematically changed by hydrothermal reaction parameters (temperature: 180-240 degrees C; volume: 40-80 %), resulting in varying shape, crystallinity, stacking form, phase, oxidation state, and HER activity. The reaction temperature and volume control can finely tune the 1T/2H phase ratio and conversion yield from Mo6+ to Mo4+, which affect HER efficiency. This brings the optimized synthesis of MoS2 on carbon cloth at 200 degrees C with 60 % reaction volume, showing the best HER overpotential of -189 mV at 10 mA cm- 2 current density. Using this condition, finally, rhenium-doped and platinum nanoparticle-deposited MoS2 composites showed overpotentials of -140 mV and -12 mV, respectively, to further improve performance. Our study contributes to the hydrothermal synthesis of two-dimensional materials for HER applications and lays the groundwork for non-precious metal-based sustainable energy catalyst development.

키워드