Rational Design of WS2/WSe2 Heterostructure by Low-Temperature Plasma-Assisted Sulphurization and Selenization Towards Enhanced HER Performance

Bushra Rehman^1,2*, K.M.M.D.K. Kimbulapitiya^1,2,3, Yu- Ren Peng^1,2, Ruei Hong Cyu^1,2, Yu Lun Chueh^1,2,3

¹Material Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan
²College of Semiconductor Research, National Tsing Hua University, Hsinchu, Taiwan
³Department of Physics, National Sun Yat-Sen UNiversity, Kaohsiung, Taiwan

* Presenter:Bushra Rehman, email:Bushra@gapp.nthu.edu.tw

The efficient hydrogen generation from water splitting underpins chemistry to realize the hydrogen economy. The electrocatalytic activity can be effectively modified by two-dimensional heterostructures, which offer great flexibility. Furthermore, they are useful in enhancing the exposure of the active sites for the hydrogen evolution reaction. Although the 1T metallic phase of the TMDs is important for the HER catalyst, its practical application has not yet been much utilized because of the lack of stability of the 1T phase. We introduce a novel approach to create a 1T-WS2/1T-WSe2 heterostructure using a low-temperature plasma-assisted chemical vapor reaction. This heterostructure exhibits superior electrocatalytic performance due to the presence of the metallic 1T phase and the beneficial synergistic effect at the interface, which is attributed to the transfer of electrons from the underlying WS2 layer to the overlying WSe2 layer. The WS2/WSe2 heterostructure catalyst demonstrates remarkable performance in the Hydrogen Evolution Reaction (HER), as evidenced by its small Tafel slope of 57 mV.dec-1 and exceptional durability. The usage of plasma helps in replacing the top S atoms with Se atoms, and this ion bombardment also increases the roughness of the thin film, thus adding another factor to enhance the HER performance. This plasma-synthesized low-temperature metallic phase heterostructure brings out a novel method for the discovery of other catalysts.

Keywords: Transition Metal Dichalcogenides (TMDs), Hydrogen evolution reaction, PACVR, Water Splitting, Heterostructure