Interfacial engineering and electronic structure modulation of two-dimensional WSe₂ towards improved electrocatalytic...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Tungsten diselenides (WSe2) are promising electrocatalysts due to tunable conductivity and stability.
• Enhancing electrocatalytic properties of transition metal dichalcogenides (TMDs) is crucial for energy applications.
• Interface engineering offers a pathway to optimize TMD electrocatalytic performance.

Purpose of the Study:

• To tune the interlayer spacing of WSe2 nanosheets (NSs) for modulating electronic properties.
• To investigate the influence of interlayer spacing on the electrocatalytic hydrogen evolution reaction (HER).
• To explore interface engineering via organic inclusion compounds for enhanced WSe2 electrocatalysis.

Main Methods:

• Solvothermal synthesis of WSe2 NSs with varying interlayer spacing using organic inclusion compounds (oleyl amine, glucose, ammonium oxalate).
• Structural and morphological characterization of synthesized WSe2 NSs.
• Electrochemical evaluation of WSe2 NSs for HER in 0.5 M H2SO4, including overpotential and Tafel slope measurements.

Main Results:

• WSe2 NSs synthesized with ammonium oxalate (WSe2-AOx) exhibited the largest interlayer spacing (0.75 nm).
• WSe2-AOx demonstrated superior HER performance with a low overpotential (268 mV at 10 mA cm-2) and Tafel slope (94 mV dec-1).
• WSe2-AOx showed excellent cycling stability (1000 cycles) and long-term durability (12 h).

Conclusions:

• Largest interlayer spacing in WSe2-AOx exposes abundant catalytic sites, accelerating HER kinetics.
• Interface engineering by tuning interlayer spacing is an effective strategy to enhance WSe2 electrocatalytic activity.
• WSe2-AOx presents a highly stable and efficient catalyst for the hydrogen evolution reaction.