Highly active and thermally stable single-atom catalysts for high-temperature electrochemical devices

Single-atom catalysts provide unique catalytic properties and maximize atom utilization efficiency. While utilizing them at elevated temperatures is highly desirable, their operating temperature is usually kept below 300°C to prevent isolated atoms from agglomerating. Moreover, their applications to high-temperature electrochemical devices have been hindered by the lack of suitable processing techniques for catalyst loading. Herein, we report single-atom Pt/ceria nanocatalysts that are highly active and thermally stable in solid oxide cell (SOC) operating at 600-800°C. Our urea-based chemical solution process creates strong Pt–O–Ce interactions that securely anchor isolated Pt atoms to the surface of ceria nanoparticles and suppress their high-temperature migration. These single-atom Pt/ceria nanocatalysts are loaded in the oxide fuel electrode of SOC via in situ synthetic process, which reduces the polarization resistance from 28.2 to 0.82 Ohm cm^2 at 600°C. This electrode outperforms the state-of-the-art Ni-based fuel electrode by up to 10 times and delivers extremely high performance in full SOCs in fuel cell and electrolysis modes. Furthermore, it stably operates at 700°C for over 500 h under realistic operating conditions. Our results provide guidance to resolve the critical issues for the practical use of single-atom catalysts in various industrial processes and accelerate the commercial development of next-generation high-temperature energy devices.