Zinc doping induced WS2 accelerating the HER and ORR kinetics: A theoretical and experimental validation

The development of non-noble-metal electrocatalysts with excellent performance and economic benefits toward the hydrogen evolution reaction (HER) is very vital for the development of future energy. Two-dimensional transition-metal sulfides, in particular, WS2 based materials, are considered to be fine alternative catalysts for the HER, where doping engineering has proven to be an effective way to tune their electrocatalytic activity. Herein, we have reported different doping concentration-based Zn-doped WS2 shows enhanced electrochemical activity compared with pure WS2. The obtained Zn-doped WS2 (WS2-30) displays excellent HER performance, having an onset potential of 180 mV at the current density of 10 mA cm−2 with a low Tafel slope of 70 mV/dec. Theoretical and experimental studies show the substantial atomic percentage of Zn in the WS2 facilitates the cathodic reduction of oxygen via the four-electron pathway with a higher limiting-diffusion current density (−4.8 mA cm−2) and higher rate constant than bulk WS2. Thus, to enhance the intrinsic activities of transition-metal sulfides, doping engineering provides an efficient method that may contribute to developing nonprecious electrocatalysts for HER.