Ham, Hyung Chul Manogaran, Dhivya Lee, Kang Hee Kwon, Kyungjung Jin, Seon-ah You, Dae Jong Pak, Chanho Hwang, Gyeong S. 2024-01-20T11:02:54Z 2024-01-20T11:02:54Z 2021-08-31 2013-11-28 0021-9606 https://pubs.kist.re.kr/handle/201004/127425 Based on a combined density functional theory and experimental study, we present that the electrochemical activity of Pd3Co alloy catalysts toward oxygen reduction reaction (ORR) can be enhanced by adding a small amount of Ir. While Ir tends to favorably exist in the subsurface layers, the underlying Ir atoms are found to cause a substantial modification in the surface electronic structure. As a consequence, we find that the activation barriers of O/OH hydrogenation reactions are noticeably lowered, which would be mainly responsible for the enhanced ORR activity. Furthermore, our study suggests that the presence of Ir in the near-surface region can suppress Co out-diffusion from the Pd3Co substrate, thereby improving the durability of Pd-Ir-Co catalysts. We also discuss the relative roles played by Ir and Co in enhancing the ORR activity relative to monometallic Pd catalysts. (C) 2013 AIP Publishing LLC. English AMER INST PHYSICS ELECTROCATALYSTS CATALYSTS Communication: Enhanced oxygen reduction reaction and its underlying mechanism in Pd-Ir-Co trimetallic alloys Article 10.1063/1.4837176 1 JOURNAL OF CHEMICAL PHYSICS, v.139, no.20 JOURNAL OF CHEMICAL PHYSICS 139 20 scie scopus 000327717000004 2-s2.0-84903369206 Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics Article ELECTROCATALYSTS CATALYSTS PEMFC Pd-Co-Ir oxygen reduction reaction