Conversion of Layered WS 2 Crystals into Mixed-Domain Electrochemical Catalysts by Plasma-Assisted Surface Reconstruction

• Published in: Advanced materials (Weinheim) Vol. 36; no. 25; p. e2314031
• Main Authors: Park, Jiheon, Cho, Iaan, Jeon, Hotae, Lee, Youjin, Zhang, Jian, Lee, Dongwook, Cho, Min Kyung, Preston, Daniel J, Shong, Bonggeun, Kim, In Soo, Lee, Won-Kyu
• Format: Journal Article
• Language: English
• Published: Germany 01-06-2024
• Subjects: catalytic materials; plasma treatment; water electrolysis; hydrogen evolution reaction; transition metal chalcogenides
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202314031

Electrocatalytic water splitting is crucial to generate clean hydrogen fuel, but implementation at an industrial scale remains limited due to dependence on expensive platinum (Pt)-based electrocatalysts. Here, an all-dry process to transform electrochemically inert bulk WS
into a multidomain electrochemical catalyst that enables scalable and cost-effective implementation of the hydrogen evolution reaction (HER) in water electrolysis is reported. Direct dry transfer of WS
flakes to a gold thin film deposited on a silicon substrate provides a general platform to produce the working electrodes for HER with tunable charge transfer resistance. By treating the mechanically exfoliated WS
with sequential Ar-O
plasma, mixed domains of WS
, WO
, and tungsten oxysulfide form on the surfaces of the flakes, which gives rise to a superior HER with much greater long-term stability and steady-state activity compared to Pt. Using density functional theory, ultraefficient atomic sites formed on the constituent nanodomains are identified, and the quantification of atomic-scale reactivities and resulting HER activities fully support the experimental observations.