We present a rapid and scalable strategy for constructing a high-performance oxygen evolution reaction (OER) electrocatalyst based on cobalt–nickel boride (CoNiB₂). Using a liquid-phase soaking technology, crystalline CoNiB₂ nanoflowers can be synthesized within seconds from simple oxide precursors. This work demonstrates that efficient, durable and non-precious-metal OER catalysts can be produced through an ultra-fast and versatile synthesis route, offering new opportunities for green hydrogen production.

Key Insights

• Ultra-fast synthesis strategy: We developed a liquid-phase soaking technology that enables the synthesis of crystalline CoNiB₂ in just 20 seconds, showing that high-performance electrocatalysts can be obtained on an exceptionally short timescale.
• Liquid boron oxide as a transient reaction medium: Molten boron oxide acts as a temporary liquid phase that promotes rapid redox conversion of cobalt and nickel oxides into CoNiB₂ while limiting crystal overgrowth, yielding phase-pure products with controlled morphology.
• Nanoflower architecture with abundant active sites: The resulting CoNiB₂ forms nanoflowers composed of folded, edge-rich subunits, greatly increasing the electrochemically active surface area and facilitating efficient charge transfer during oxygen evolution.
• Outstanding oxygen evolution activity: In alkaline electrolyte, CoNiB₂ reaches 10 mA cm⁻² at an overpotential of only 271 mV, outperforming the benchmark RuO₂ catalyst at comparable loading.
• Fast reaction kinetics enabled by bimetallic synergy: A low Tafel slope of 67 mV dec⁻¹ indicates accelerated OER kinetics, arising from the synergistic electronic interaction between cobalt and nickel within the boride lattice.
• Excellent durability under high current density: The CoNiB₂ catalyst maintains stable performance during continuous operation at 100 mA cm⁻² for at least 25 hours, underscoring its robustness under industrially relevant conditions.
• Theoretical insight into performance enhancement: Density functional theory calculations reveal that CoNiB₂ exhibits a much lower energy barrier for the rate-determining step of OER than monometallic CoB, providing mechanistic insight into its superior catalytic activity.

Significance

This study shows that efficient and durable OER catalysts can be synthesized rapidly without relying on precious metals or complex processing routes. The ability to fabricate a high-performance bimetallic boride catalyst within seconds offers a practical pathway toward scalable catalyst production for alkaline water electrolysis and green hydrogen technologies.

More broadly, the liquid-phase soaking approach provides a general strategy for constructing nanoscale borides with tailored morphology and optimized electronic structure. This method can be extended to other boride systems, accelerating materials discovery in electrocatalysis and energy conversion.

Authors and Author Affiliations

Ruifeng Qi†, Junqi Liu†, Xiaohua Qiao, Tianyu Zhang, Qin Liu, Feng Gao, Qingsong Huang*
† These authors contributed equally to this work

School of Chemical Engineering, Sichuan University, Chengdu 610065, China
Tianfu Jiangxi Laboratory, Chengdu 610065, China

Corresponding Author: Qingsong Huang
Email: qshuang@scu.edu.cn