Abstract

Heterogeneous catalysts comprising metal nanoparticles (NPs) on oxide supports are widely employed in high-temperature electrochemical devices such as solid oxide cells (SOCs). Unfortunately, these catalysts frequently exhibit structural instability at metal-oxide interfaces due to lattice mismatch, resulting in diminished catalytic activity and overall performance degradation over time. This work introduces an unprecedented approach of synthesizing intermetallic supports with metal-metal junctions by utilizing layered double hydroxide (LDH) structures. The LDH-derived framework undergoes controlled phase transitions, yielding an intermetallic structure decorated with exsolved Co─Fe alloy nanoparticles under reducing conditions, which would be the key for effectively mitigating the interfacial strain. This engineered electrode demonstrates exceptional electrocatalytic activity toward fuel oxidation reaction at high temperature regimes above 700°C. Furthermore, composite formation with oxygen ion conductive Gd0.1Ce0.9O2-δ (GDC) simultaneously augments electrochemical performance and structural stability, achieving a peak power density of 1.57 W cm−2 at 800°C under H2 fuel, while maintaining stable operation under SOC operations. This work hence presents an innovative strategy for designing structurally robust, efficient, and durable metal-metal junctions, thereby advancing the fields of high-temperature electrochemistry and catalysis.

A research team affiliated with UNIST has unveiled a novel electrode material that significantly enhances the performance and stability of high-temperature electrochemical devices capable of converting carbon dioxide (CO2) into valuable chemicals while simultaneously generating electricity.

Led by Professor Seungho Cho of the Department of Materials Science and Engineering at UNIST, the team collaborated with researchers from POSTECH, Seoul National University, and Nanjing University of Information Science and Technology (NUIST) to develop a metal-supported solid oxide cell (SOC) electrode utilizing layered double hydroxides (LDHs). This innovative design sustains high efficiency at temperatures exceeding 700°C, effectively addressing longstanding stability challenges associated with conventional ceramic-supported electrodes.

The new electrode achieved a maximum power density of 1.57 W/cm² at 800°C—approximately 50% higher than existing solutions—and demonstrated stable operation over 200 hours during CO2 reduction to carbon monoxide. Its all-metal construction ensures resilience against thermal degradation, a common obstacle in high-temperature applications.

This breakthrough leverages the distinctive properties of LDHs, layered materials containing uniformly dispersed cobalt and iron ions. Through controlled thermal processing, the researchers induced phase transformations that facilitate the formation of metal-metal junctions and promote the exsolution of catalytic nanoparticles. These processes effectively alleviate interfacial strain and significantly enhance durability.

In addition, the incorporation of gadolinium-doped ceria (GDC) further optimized oxygen ion transport, thereby improving overall electrochemical performance.

The research team noted, “Reducing electrode replacement lowers operational costs and accelerates the deployment of clean energy technologies. Our approach offers a versatile pathway toward sustainable fuel and chemical production from CO2.” 

They further stated, "This study pioneers the high-temperature application of layered double hydroxides in solid oxide electrodes—an advancement with far-reaching implications for energy efficiency and environmental sustainability."

Contributing researchers include Hyunmin Kim (currently at Stanford University), Yoon Seo Kim (currently at Korea Institute of Science and Technology), and Hwakyoung Seo from Seoul National University, as first authors. The findings were published in Advanced Functional Materials on April 16, 2026. This research was supported by the InnoCORE program of UNIST and the National Research Foundation of Korea (NRF).

Journal Reference

Hyunmin Kim, Zhengyu Wu, Yoon Seo Kim, et al., "Engineering Metal-Metal Junctions from Layered Double Hydroxide Frameworks for High-Rate Solid Oxide Cells," (2026).