Quasi-Chimney Electrode Boosts Hydrogen Evolution Reaction via Polarized Laplace Pressure

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Mass transfer limitations significantly hinder hydrogen evolution reaction (HER) efficiency at high current densities.
• Efficient bubble management and reduced dissolved hydrogen are critical for optimizing HER performance.

Purpose of the Study:

• To investigate the impact of mass transfer on HER under high current densities.
• To design and evaluate a novel electrode structure that enhances mass transfer for improved HER.

Main Methods:

• Fabrication of a quasi-chimney electrode integrating 3D superaerophilic microchannels with superaerophobic platinum (Pt) catalysts.
• Analysis of bubble dynamics and mass transfer mechanisms using the designed electrode.
• Electrochemical testing to evaluate HER performance, including overpotential, current density, and durability.

Main Results:

• The quasi-chimney electrode demonstrated exceptional HER performance, achieving a record-low overpotential of approximately -30 mV at -100 mA cm⁻².
• A high current density of -2.93 A cm⁻² at -0.3 V vs RHE was recorded in 0.5 M H₂SO₄.
• The design showed remarkable durability with <5% activity decay at -1000 and -2000 mA cm⁻² for 160 hours.
• The quasi-chimney design led to an 8- and 14-fold increase in current density for Cu-Co and Cu-Mo catalysts, respectively.

Conclusions:

• The quasi-chimney electrode design effectively addresses mass transfer limitations in HER.
• This innovative design significantly enhances hydrogen bubble transport and reduces dissolved hydrogen concentration.
• The approach offers a scalable strategy for improving HER efficiency across various catalytic materials.