The Korea Institute of Science and Technology (KIST) announced that Dr. Kyung-Joong Yoon and Researcher Ji-Su Shin from the Center for Energy Materials Research, together with Professor Yun -Jung Lee from Hanyang University (Hanyang University, President Woo-Seung Kim), have developed a single-atom Pt catalyst that can be used for SOFCs.
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 cm2 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.—Shin et al.
In their research, entire platinum atoms are evenly distributed and function individually without agglomeration even at high temperatures. It has been experimentally shown to increase the electrode reaction rate by more than 10 times.
SEM images of (a) the inner surface of fuel electrode before (left) and after (right) infiltration and (b) the entire fuel electrode, including the interfacial region between functional and current collecting layers. Shin et al.
It can also operate for more than 500 hours even at high temperatures up to 700 ˚C and improves the electric power generation and hydrogen production performance by 3-4 times. It is expected to accelerate the commercialization of solid oxide fuel cells (SOFCs), the next-generation eco-friendly fuel cells.
A paper on their work is published in the journal Energy & Environmental Science.
The single-atom catalyst jointly developed by KIST-Hanyang University research team is made by combining platinum atoms and cerium (Ce) oxide nanoparticles. Each platinum atom is individually dispersed on the surface of the cerium oxide nanoparticles, and the strong bond maintains the dispersed state of the atoms for a long duration of time even at high temperatures, which allows all platinum atoms to be involved in the reaction. This in turn makes it possible to substantially improve the rate of the electrode reaction while minimizing the amount of platinum used.
For the fabrication, a solution containing platinum and cerium ions is injected into the electrode of the SOFC, and the catalysts are synthesized while the fuel cell is operating at a high temperature. Because the injection into the electrode can be performed easily without any special equipment, it expected that the newly developed catalyst can readily be applied to existing fuel cell fabrication processes.
The catalyst developed in this study can be applied to a wide variety of solid oxide fuel cells and high-temperature electrochemical devices using an easy and simple low-cost process, so it is expected to accelerate the development of next-generation eco-friendly power generation and energy storage devices.
Based on the fact that the single-atom catalyst can operate stably even at 700 degrees Celsius or higher, its application fields will be greatly expanded, including high-temperature thermochemical reactions and high-temperature electrochemical reactions.—Dr. Kyung-Joong Yoon from KIST
This study was carried out with a grant from the Ministry of Science and ICT (MSIT), as part of the Institutional R&D Program of KIST and the Korea Research Foundation’s Program on Development of Technology in Response to Climate Change.
Jisu Shin, Young Joo, Asif Jan, Sung Min Choi, Mi Young Park, Sungjun Choi, Jun Yeon Hwang, Seungki Hong, Seung Gyu Park, Hye Jung Chang, Min Kyung Cho, Jitendra Pal Singh, Keun Hwa Chae, Sungeun Yang, Ho-Il Ji, Hyoungchul Kim, Ji-Won Son, Jong-Ho Lee, Byung-Kook Kim, Hae-Weon Lee, Jongsup Hong, Yun Jung Lee and Kyung Joong Yoon (2020) “Highly active and thermally stable single-atom catalysts for high-temperature electrochemical devices” Energy Environ. Sci. doi: 10.1039/D0EE01680B