Plasma tailoring in WTe2 nanosheets for efficiently boosting hydrogen evolution reaction

2D transition metal dichalcogenides (TMDs) have been considered as promising non-precious electro-catalysts for the hydrogen evolution reaction (HER). However, their limited active sites and poor electric conductivity pose a significant hurdle to their HER performance, resulting in a large overpotential. Here, we report the defect engineering in ultrathin tungsten telluride (WTe2) nanosheets with semimetal nature to improve hydrogen evolution effectively. We find that the oxygen plasma etching imposes a cutting effect on WTe2 nanosheets, resulting in a large number of tungsten vacancies. Particularly, the sample after plasma treatment for 10 min shows a feather-like structure with an overpotential of 251 mV at 10 mA/cm(2) and a Tafel slope of 94 mV/dec, which is 4 times lower than the Tafel slope of pristine nanosheets. Further first-principles calculations shed light on the evolution of defect-rich WTe2 nanosheets and offer rational explanation to their superiority in efficient hydrogen evolution. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

Defect engineering in ultrathin tungsten telluride nanosheets improves hydrogen evolution by introducing tungsten vacancies through oxygen plasma etching, leading to a significant reduction in overpotential and Tafel slope for more efficient performance.