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.