Multifunctional 2H-TaS2 nanoflake efficient for supercapacitors, electrocatalytic evolution of hydrogen and oxygen
Layered transition-metal dichalcogenides (e.g., MoS2, WSe2, et al.) based on VIB elements have attracted numerous attention to energy storage and conversion devices. However, few researches have concentrated on VB element dichalcogenides. Here we reported that trifunctional 2H-TaS2 nanoflakes exhibit high-performance for supercapacitor, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Notably, TaS2 nanoflakes delivered large volumetric capacitance (502 F cm-3 at the scan rate of 10 mV s-1) and remarkable cycling stability (over 91% after 5000 cycles). In HER, TaS2 nanoflakes show an overpotential of 145 mV at -10 mA cm-2 with low Tafel slope of 121 mV dec-1. These values are much superior to those previously reported TaS2 materials from literatures. Besides, TaS2 nanoflakes also exhibited remarkable catalytic performance in OER process, showing a very small overpotential of 315 mV at 10 mA cm-2 and Tafel slope of 81 mV dec-1, which are far exceeding those of commercial RuO2. Furthermore, TaS2 is highly stable in both alkaline and acidic electrolyte. This work offers a new concept to design VB elements-based electrodes in future energy storage and conversion.