Kim, Jeonghyeon Kim, Hee Jin Ruqia, Bibi Kim, Mi Ji Jang, Yeong-Ji Jo, Tae Hwan Baik, Hionsuck Oh, Hyung-Suk Chung, Hee-Suk Baek, Kangkyun Noh, Siwoo Jung, Moonjung Kim, Ki-jeong Lim, Hyung-Kyu Youn, Young-Sang Choi, Sang-Il 2024-01-19T13:04:21Z 2024-01-19T13:04:21Z 2022-01-10 2021-12 0935-9648 https://pubs.kist.re.kr/handle/201004/116009 Although metastable crystal structures have received much attention owing to their utilization in various fields, their phase-transition to a thermodynamic structure has attracted comparably little interest. In the case of nanoscale crystals, such an exothermic phase-transition releases high energy within a confined surface area and reconstructs surface atomic arrangement in a short time. Thus, this high-energy nanosurface may create novel crystal structures when some elements are supplied. In this work, the creation of a ruthenium carbide (RuCX, X < 1) phase on the surface of the Ru nanocrystal is discovered during phase-transition from cubic-close-packed to hexagonal-close-packed structure. When the electrocatalytic hydrogen evolution reaction (HER) is tested in alkaline media, the RuCX exhibits a much lower overpotential and good stability relative to the counterpart Ru-based catalysts and the state-of-the-art Pt/C catalyst. Density functional theory calculations predict that the local heterogeneity of the outermost RuCX surface promotes the bifunctional HER mechanism by providing catalytic sites for both H adsorption and facile water dissociation. English WILEY-V C H VERLAG GMBH RUTHENIUM NANOPARTICLES REDUCTION NANOSTRUCTURES CATALYST OXIDE PH OXOPHILICITY METALS HEAT ACID Crystal Phase Transition Creates a Highly Active and Stable RuCX Nanosurface for Hydrogen Evolution Reaction in Alkaline Media Article 10.1002/adma.202105248 1 ADVANCED MATERIALS, v.33, no.48 ADVANCED MATERIALS 33 48 scie scopus 000703764200001 2-s2.0-85116320387 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article RUTHENIUM NANOPARTICLES REDUCTION NANOSTRUCTURES CATALYST OXIDE PH OXOPHILICITY METALS HEAT ACID alkaline media hydrogen evolution reaction nanosurfaces phase transitions ruthenium carbide