Kwon, Jiseok Sun, Seho Choi, Seunggun Lee, Kangchun Jo, Seonghan Park, Keemin Kim, Young Kwang Park, Ho Bum Park, Hee Young Jang, Jong Hyun Han, Hyuksu Paik, Ungyu Song, Taeseup 2024-01-19T09:31:44Z 2024-01-19T09:31:44Z 2023-05-25 2023-06 0935-9648 https://pubs.kist.re.kr/handle/201004/113694 Proton-exchange-membrane water electrolysis (PEMWE) requires an efficient and durable bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, Ir-based electrocatalyst is designed using the high entropy alloy (HEA) platform of ZnNiCoIrX with two elements (X: Fe and Mn). A facile dealloying in the vacuum system enables the construction of a nanoporous structure with high crystallinity using Zn as a sacrificial element. Especially, Mn incorporation into HEAs tailors the electronic structure of the Ir site, resulting in the d-band center being far away from the Fermi level. Downshifting of the d-band center weakens the adsorption energy with reaction intermediates, which is beneficial for catalytic reactions. Despite low Ir content, ZnNiCoIrMn delivers only 50 mV overpotential for HER at -50 mA cm(-2) and 237 mV overpotential for the OER at 10 mA cm(-2). Furthermore, ZnNiCoIrMn shows almost constant voltage for the HER and OER for 100 h and a high stability number of 3.4 x 10(5) n(hydrogen) n(Ir)(-1) and 2.4 x 10(5) n(oxygen) n(Ir)(-1), demonstrating the exceptional durability of the HEA platform. The compositional engineering of ZnNiCoIrMn limits the diffusion of elements by high entropy effects and simultaneously tailors the electronic structure of active Ir sites, resulting in the modified cohesive and adsorption energies, all of which can suppress the dissolution of elements. English WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Tailored Electronic Structure of Ir in High Entropy Alloy for Highly Active and Durable Bifunctional Electrocatalyst for Water Splitting under an Acidic Environment Article 10.1002/adma.202300091 1 Advanced Materials, v.35, no.26 Advanced Materials 35 26 N scie scopus 000985791300001 2-s2.0-85158844892 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article OXYGEN EVOLUTION PEROVSKITE REDUCTION OXIDATION CATALYSTS LIGAND bifunctional electrocatalysts compositional engineering high entropy alloys PEM electrolysis