Separating nanobubble nucleation for transfer-resistance-free electrocatalysis

Area of Science:

• Electrocatalysis
• Materials Science
• Surface Chemistry

Background:

• Electrocatalytic reactions generate bubbles that hinder mass transfer and reduce efficiency.
• High current densities exacerbate bubble coverage, leading to potential cell failure.
• Controlling bubble dynamics is crucial for improving electrocatalyst performance.

Purpose of the Study:

• To develop an operando imaging technique for visualizing bubble nucleation and dynamics.
• To investigate the role of interfacial metal layers in bubble formation during hydrogen evolution.
• To enhance electrocatalytic activity by controlling bubble nucleation sites.

Main Methods:

• On-chip microcell coupled with total-internal-reflection-fluorescence-microscopy for sub-50 nm bubble imaging.
• Utilized platinum-interfacial metal layer-graphene as model electrocatalytic systems.
• Operando dynamic probing of bubble nucleation during hydrogen evolution reaction.

Main Results:

• Demonstrated visualization of bubble nucleation and growth dynamics at the nanoscale.
• Showcased that strong binding in Pt-interfacial metal-graphene enhances hydrogen spillover to graphene.
• Observed spatial separation of bubble nucleation from the platinum surface, reducing interference.
• Achieved significantly enhanced catalytic activity in both microcell and membrane cell tests.

Conclusions:

• The developed microscopy technique provides unprecedented insights into bubble behavior during electrocatalysis.
• Interfacial engineering of metal-graphene supports can effectively control bubble nucleation.
• Optimized interfaces minimize mass transfer resistance, leading to superior electrocatalytic performance and stability.