During a long-term operation of polymer electrolyte membrane fuel cells(PEMFCs), the fuel cell performance may degrade due to severe agglomeration and dissolution of metal nanoparticles in the cathode. To enhance the electrochemical durability of metal catalysts and to prevent the particle agglomeration in PEMFC operation, this paper proposes a hybrid catalyst structure composed of PtCo alloy nanoparticles encapsulated by porous carbon layers. In the hybrid catalyst structure, the dissolution and migration of PtCo nanoparticles can be effectively prevented by protective carbon shells. In addition, O2 can properly penetrate the porous carbon layers and react on the active Pt surface, which ensures high catalytic activity for the oxygen reduction reaction. Although the hybrid catalyst has a much smaller active surface area due to the carbon encapsulation compared to a commercial Pt catalyst without a carbon layer, it has a much higher specific activity and significantly improved durability than the Pt catalyst. Therefore, it is expected that the designed hybrid catalyst concept will provide an interesting strategy for development of high-performance fuel cell catalysts.

Abstract
 1. 서 론
 2. 실험 방법
 3. 결과 및 고찰
 4. 결 론
 References

• 장정희(충남대학교 에너지과학기술대학원) | Jeonghee Jang (Graduate School of Energy Science and Technology, Chungnam National University)
• 모니카 샤르마(충남대학교 에너지과학기술대학원) | Monika Sharma (Graduate School of Energy Science and Technology, Chungnam National University)
• 성후광(충남대학교 에너지과학기술대학원) | Hukwang Sung (Graduate School of Energy Science and Technology, Chungnam National University)
• 김순표(충남대학교 에너지과학기술대학원) | Sunpyo Kim (Graduate School of Energy Science and Technology, Chungnam National University)
• 정남기(충남대학교 에너지과학기술대학원) | Namgee Jung (Graduate School of Energy Science and Technology, Chungnam National University) Corresponding author