Active hydrogen evolution on the plasma-treated edges of WTe₂

The tuning catalytic functionality of transition metal dichalcogenides (TMDs) with multi-dimensional defects, such as interfaces (2D), edges (1D), and atomic vacancies (0D), is currently considered a promising strategy for energy applications. The pristine edges and plasma-treated basal planes of various TMDs have been extensively studied for practical hydrogen evolution reaction (HER). Here, we demonstrate active HER on the plasma-treated edges of semimetallic layered tungsten ditellurides (WTe₂) using a microcell device. Atomic defects, substitutions, and new chemical bonds were locally induced on the basal plane and the edges of WTe₂ by mild plasma treatment, leading to catalytically activated WTe₂ for HER. The plasma treated WTe₂ was characterized by Raman spectroscopy and x-ray photoemission spectroscopy. The local HER at the plasma-treated edges in the microcell device exhibited active electrocatalytic activity with an improved overpotential (325 mV at 10 mA/cm²) and Tafel slope (96 mV/dec), compared with pristine WTe₂ (overpotential of 538 mV at 10 mA/cm² and Tafel slope of 145 mV/dec). Our study proposes a novel strategy to tune the catalytic functionality with multi-dimensional defects for practical catalytic applications.