Boosting Activity and Stability for the Alkaline Hydrogen Oxidation Reaction via Surface Reconstruction of Cu‐Ni Core–Shell Electrocatalysts Through Oxygen Intercalation

Why It Matters

The breakthrough offers a scalable, PGM‑free solution that simultaneously boosts alkaline HOR activity and long‑term stability, addressing a key bottleneck for fuel‑cell and electrolyzer technologies. Enhanced durability reduces replacement costs and accelerates commercialization of green hydrogen systems.

Key Takeaways

• Surface reconstruction via nitric acid etching improves HOR activity.
• Oxygen intercalation stabilizes Ni against anodic oxidation.
• Cu redistribution optimizes hydrogen and hydroxyl binding energies.
• Catalyst retains 93.5% activity after 10,000 cycles.
• Delivers 2.33 mA cm⁻² at 100 mV overpotential.

Pulse Analysis

Alkaline hydrogen oxidation is a cornerstone reaction for next‑generation fuel cells and electrolyzers, yet its commercial rollout has been hampered by reliance on platinum‑group metals. Nickel‑based catalysts are attractive for cost reasons but suffer from suboptimal hydrogen binding energy (HBE) and hydroxyl binding energy (OHBE), leading to sluggish kinetics and rapid degradation under anodic conditions. Researchers have therefore been searching for strategies that can simultaneously adjust these electronic parameters while protecting the catalyst surface from oxidation.

The new approach leverages a controlled nitric‑acid etching step that strips away a Ni‑rich surface layer and drives oxygen atoms into the upper ten atomic layers of a Cu‑Ni core‑shell structure. This oxygen intercalation shifts the Ni d‑band center downward, fine‑tuning the HBE, while the presence of interfacial oxygen modifies orbital alignment to strengthen OHBE. Concurrently, copper atoms migrate toward the surface, stabilizing the bimetallic framework and preventing Ni dissolution. The resulting Cu@Oi‑NiCu electrocatalyst exhibits a current density of 2.33 mA cm⁻² at just 100 mV overpotential and a kinetic current of 5.26 mA cm⁻², outperforming many conventional nickel catalysts.

Beyond the laboratory, this surface‑reconstruction technique offers a scalable pathway to produce durable, PGM‑free HOR catalysts for large‑scale hydrogen infrastructure. By delivering both high activity and exceptional cycle life—maintaining over 93% performance after 10,000 cycles—the technology can lower capital expenditures for fuel‑cell stacks and electrolyzer modules. Its underlying principles are also applicable to other transition‑metal systems, suggesting broader relevance for renewable energy conversion and storage solutions.