Coupling Hydrogen Spillover at Synergistic PtNi/NiInOx Interfaces with Urea Oxidation for Enhancing Water Splitting

Why It Matters

The breakthrough cuts precious‑metal usage and energy demand, making large‑scale hydrogen production more economical and environmentally sustainable.

Key Takeaways

• PtNi alloy enables hydrogen spillover via low work function.
• Ultra-low Pt loading (1.6 wt %) achieves 13 mV overpotential.
• Coupled urea oxidation reduces cell voltage to 1.42 V.
• Catalyst stable >188 h at 100 mA cm⁻² in seawater.
• Near‑100 % Faradaic efficiency for urea‑assisted water splitting.

Pulse Analysis

Hydrogen spillover—where adsorbed hydrogen atoms migrate from a metal catalyst to a neighboring support—has long been touted as a route to boost electrocatalytic efficiency, yet practical implementations remain scarce. The PtNi/NiInOx system leverages a deliberately engineered work‑function mismatch that weakens the Schottky barrier, allowing hydrogen atoms to transfer seamlessly from the Pt‑rich alloy to the nickel‑indium oxide matrix. This interfacial pathway not only accelerates the adsorption‑transfer‑desorption cycle but also sidesteps the need for bulk platinum, addressing a critical cost barrier in green‑hydrogen technologies.

Performance data underscore the commercial relevance of the architecture. With merely 1.6 wt % platinum, the catalyst reaches an overpotential of 13 mV at 10 mA cm⁻²—among the lowest reported for alkaline HER—while sustaining more than 188 hours of continuous operation at 100 mA cm⁻². Its resilience extends to simulated seawater and photovoltaic‑driven setups, indicating compatibility with emerging off‑grid hydrogen hubs. By maintaining high activity under realistic, impurity‑laden conditions, the material bridges the gap between laboratory breakthroughs and field deployment.

The integration of urea oxidation further amplifies the system’s appeal. Urea, an abundant by‑product of agricultural and wastewater streams, oxidizes at a lower potential than the oxygen evolution reaction, slashing the overall cell voltage to 1.425 V for 50 mA cm⁻² operation. This energy saving translates into lower electricity costs and a higher net hydrogen yield, while the near‑100 % Faradaic efficiency confirms minimal side reactions. As industries seek carbon‑neutral pathways, the PtNi‑NiInOx catalyst paired with urea oxidation offers a scalable, cost‑effective platform poised to accelerate the transition to a hydrogen‑centric energy economy.