Manganese Doping of MoSe₂ Promotes Active Defect Sites for Hydrogen Evolution.

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Transition-metal dichalcogenides (TMDs) are promising alternatives to precious metal catalysts for the hydrogen evolution reaction (HER).
• High onset potentials of TMDs hinder their widespread application in HER.
• Developing efficient and cost-effective catalysts for HER is crucial for clean energy technologies.

Purpose of the Study:

• To synthesize Mn-doped MoSe2 nanoflowers using a one-pot method.
• To investigate the effect of substitutional Mn-doping on the HER performance of MoSe2.
• To elucidate the mechanism by which Mn-doping enhances HER activity.

Main Methods:

• One-pot synthesis of substitutional Mn-doped MoSe2 nanoflowers.
• Electron microscopy and elemental characterization (e.g., EDX) to confirm doping and structure.
• Density Functional Theory (DFT) calculations to understand the role of dopants.

Main Results:

• Achieved substitutional Mn-doping in MoSe2 nanoflowers without dopant clustering.
• Demonstrated a significant reduction in HER overpotential and improved charge-transfer kinetics.
• DFT calculations revealed Mn-dopants promote Se-vacancy formation, which are the active sites for HER.

Conclusions:

• Substitutional Mn-doping is an effective strategy to enhance the HER activity of MoSe2.
• The enhanced performance is attributed to Mn-dopants promoting catalytically active selenium vacancies.
• This approach offers a new pathway for activating TMD catalysts for electrochemical reactions.