Presentation Information
[2G05]Caffeine-assisted solvothermal synthesis of 1T-MoS2 without strong reducing agents: structural characterization and enhanced HER performance
*Hiroki Waizumi1, Ryunosuke Tange1, Seiya Yokokura1, Toshihiro Shimada1 (1. Hokkaido University)
We report a caffeine-assisted solvothermal synthesis of 1T-phase MoS2 without strong reducing agents. Caffeine, a mild electron donor with weak reducing power, was added to (NH4)6Mo7O24 and thiourea in water and reacted at 140–200 °C for 24 h. XRD showed (002) peak shift from 14.4° to 9.5° and appearance of a (004) reflection, indicating interlayer expansion and phase transition. Raman revealed J1–J3 peaks (150–230 cm-1) specific to 1T-MoS2. XPS showed ~1.0 eV binding energy shifts to lower values, consistent with electron transfer from caffeine and metallic phase stabilization. TEM confirmed irregular, expanded interlayers without sulfur deficiency. HER tests showed marked improvement: onset potential from –668 mV to –268 mV and Tafel slope from –180 to –110 mV dec-1, attributed to enhanced conductivity, electrolyte penetration, and active site exposure. This safe, effective method offers a new route to highly conductive 1T-MoS2 for catalytic applications.