Hydrogen Spillover by Synergy at Ir─O─Ru Interfaces for Ampere-Level Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Industrial hydrogen production relies on alkaline water electrolysis.
• The Volmer step in electrolysis is a kinetic bottleneck, limiting efficiency.
• Electrocatalysts need to sustain high current densities for industrial viability.

Purpose of the Study:

• To develop a novel electrocatalyst for efficient alkaline water electrolysis.
• To engineer the catalyst's surface microenvironment for improved kinetics.
• To investigate the mechanism behind enhanced hydrogen evolution.

Main Methods:

• Synthesized atomically dispersed iridium on ruthenium nanoparticles.
• Utilized surface hydroxyl and defect oxygen sites for coordination.
• Employed density functional theory (DFT) for mechanistic studies.
• Tested catalyst performance in alkaline solutions and electrolyzers.

Main Results:

• Formed electronically coupled Ir─O─Ru interfacial ensembles.
• Revealed a cooperative hydrogen-spillover mechanism via DFT.
• Achieved 1.0 A cm^-2 at 103 mV overpotential in 1.0 M KOH.
• Demonstrated exceptional durability exceeding 3000 hours at 1.0 A cm^-2.
• Maintained stable operation in alkaline seawater and an anion-exchange-membrane electrolyzer.

Conclusions:

• Surface microenvironment engineering with single-atom decoration is effective.
• The Ir─O─Ru interface facilitates water activation and hydrogen evolution.
• The catalyst offers a viable strategy for high-flux alkaline hydrogen production.