Min, Jiho Lee, Jeong Hee Ko, Keonwoo Kim, Yunjin Park, Hyelim Kim, Mansu Lee, Dongwook Yim, Sung-dae Kang, Yun Sik Hupp, Joseph T. Yoo, Sung Jong Jung, Namgee 2026-02-19T07:00:20Z 2026-02-19T07:00:20Z 2026-02-19 2026-02 1613-6810 https://pubs.kist.re.kr/handle/201004/154328 Over recent decades, extensive efforts have aimed to enhance fuel cell performance. Pt alloys with 3d transition metals are particularly attractive for boosting oxygen reduction reaction (ORR) activity via strain and electronic effects. However, their structural instability and high Pt usage hinder practical application. Here, we report a highly active and durable catalyst with reduced Pt cost, achieved by integrating a Pt-segregated surface and porous carbon shell. Unlike conventional polymer-coating and carbonization methods, this catalyst is synthesized through a novel ‘in situ one-step’ process that simultaneously induces Pt segregation and carbon shell formation. This streamlined approach not only simplifies synthesis but also significantly lowers Pt consumption while maintaining superior ORR activity and long-term durability. As a result, the Pt content is reduced to ∼55% of that in commercial catalysts, while preserving high catalytic activity. Under single-cell testing, the catalyst exhibits excellent activity and durability, meeting DOE targets even at a Pt loading of 0.02 mg cm−2, only one-tenth of conventional loadings (0.2 mg cm−2). Therefore, this strategy provides a promising pathway toward low-cost, high-performance fuel cell catalysts, offering a practical alternative to conventional core–shell or carbon-coating approaches. English Wiley - V C H Verlag GmbbH & Co. In Situ Surface Reconstruction and Carbon Encapsulation for High-Performance Pt-Lean Catalysts beyond Conventional Core–Shell Designs Article 10.1002/smll.202511516 1 Small Small Y scie 2-s2.0-105029759590 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article; Early Access OXYGEN REDUCTION REACTION STABLE ELECTROCATALYSTS ALLOY ELECTROCATALYSTS ENHANCED ACTIVITY NANOPARTICLES DURABILITY SEGREGATION in situ one-step process oxygen reduction reaction polymer electrolyte membrane fuel cells porous carbon shell PtCo alloy Pt segregation ultralow Pt