Femtosecond Laser-Ablated Copper Surface as a Substrate for a MoS₂-Based Hydrogen Evolution Reaction Electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Improving heterogeneous electrocatalyst performance is crucial for energy applications.
• Dispersing catalytic materials on structured substrates enhances surface area and activity.

Purpose of the Study:

• To prepare and characterize a novel copper/molybdenum sulfide (Cu/MoS2) electrocatalyst.
• To evaluate its efficiency for the hydrogen evolution reaction (HER) in acidic media.

Main Methods:

• Femtosecond laser ablation to create ordered, rough copper surfaces.
• Electrochemical deposition of molybdenum sulfide (MoS2) onto copper substrates.
• Characterization using profilometry, scanning electrochemical microscopy, and electrochemical impedance spectroscopy.

Main Results:

• Fabricated fs-Cu/MoS2 electrodes exhibit significantly increased developed surface area.
• Achieved high HER performance: 10 mA cm-2 at -181 mV overpotential with a Tafel slope of ~39 mV dec-1.
• Electrochemical impedance spectroscopy revealed up to a five-fold increase in double-layer capacitance.

Conclusions:

• The fs-Cu/MoS2 electrodes demonstrate superior catalytic activity for HER.
• The entire surface of the fabricated electrodes is active for hydrogen evolution.
• Surface structuring via laser ablation is an effective strategy to enhance electrocatalyst performance.