Electrocatalysis on Edge-Rich Spiral WS₂ for Hydrogen Evolution

Abstract

Transition metal dichalcogenides (TMDs) exhibit promising catalytic properties for hydrogen generation, and several approaches including defect engineering have been shown to increase the active catalytic sites. Despite preliminary understandings in defect engineering, insights on the role of various types of defects in TMDs for hydrogen evolution catalysis are limited. Screw dislocation-driven (SDD) growth is a line defect and yields fascinating spiral and pyramidal morphologies for TMDs with a large number of edge sites, resulting in very interesting electronic and catalytic properties. The role of dislocation lines and edge sites of these spiral structures on their hydrogen evolution catalytic properties is unexplored. Here we show that the large number of active edge sites connected together by dislocation lines in the vertical direction for a spiral WS 2 domain results in exceptional catalytic properties toward hydrogen evolution reaction. A micro-electrochemical cell fabricated by photo-and electron beam-lithography processes is used to study the electrocatalytic activity of a single spiral WS 2 domain, controllably grown by chemical vapor deposition. Conductive atomic force microscopy studies show improved vertical conduction for the spiral domain, which is compared with monolayer and mechanically exfoliated thick WS 2 flakes. The obtained results are interesting and shed light on the role of SDD line defects, which contribute to large number of edge sites without compromising the vertical electrical conduction, on the electrocatalytic properties of TMDs for hydrogen evolution.

One-Pot Synthesis of W2C/WS2 Hybrid Nanostructures for Improved Hydrogen Evolution Reactions and Supercapacitors

“…To overcome the ever-increasing energy necessities, researchers have devoted considerable attention to designing and developing new and eco-friendly materials for electrochemical energy production and storage uses [1,2]. Among the various electrochemical storage devices, supercapacitors (SCs) are highly favored, owing to their quick charge-discharge ability, great power density, robust cycling constancy, and simple configuration [3].…”

Defect Engineering in Metastable Phases of Transition‐Metal Dichalcogenides for Electrochemical Applications

“…On the basis of the electrochemical microcell measurements, Shaijumon et al. investigated the electrocatalytic activity of spiral WS 2 and further confirmed that enhanced HER performance originates from the increased number of edge sites and improved vertical electrical conduction [47] …”

“…On the basis of the electrochemical microcell measurements, Shaijumon et al investigated the electrocatalytic activity of spiral WS 2 and further confirmed that enhanced HER performance originates from the increased number of edge sites and improved vertical electrical conduction. [47] Similarly, the stepped edge structure with jagged contrast is also a kind of consecutive line defects in TMDs. [48] Ajayan et al provided a simple strategy for the formation of WS 2 /MoS 2 stepped heterostructures by epitaxially growing WS 2 atop the single-layer MoS 2 at high temperature.…”

Single‐Atom and Dual‐Atom Electrocatalysts Derived from Metal Organic Frameworks: Current Progress and Perspectives

“…Tungsten-based materials such as WC, WN and WS 2 are also high active HER species. [98][99][100] In a recent work, single W atoms catalysts anchored on N doped carbon (W-SAC) were demonstrated to be more active than WC and WN. [101] As shown in Figure 11A, WCl 5 was first encapsulated in the framework of UiO-66-NH 2 .…”