biostudies-literatureLiao FMinistry of Science and Technology of the People's Republic of China (Chinese Ministry of Science and Technology)Ministry of Science and Technology of the People's Republic of China1248https://www.ebi.ac.uk/biostudies/studies/S-EPMC9985653biostudies-literatureUnknown14(1)Metastable metal oxides with ribbon morphologies have promising applications for energy conversion catalysis, however they are largely restricted by their limited synthesis methods. In this study, a monoclinic phase iridium oxide nanoribbon with a space group of C2/m is successfully obtained, which is distinct from rutile iridium oxide with a stable tetragonal phase (P42/mnm). A molten-alkali mechanochemical method provides a unique strategy for achieving this layered nanoribbon structure via a conversion from a monoclinic phase K_0.25IrO₂ (I2/m (12)) precursor. The formation mechanism of IrO₂ nanoribbon is clearly revealed, with its further conversion to IrO₂ nanosheet with a trigonal phase. When applied as an electrocatalyst for the oxygen evolution reaction in acidic condition, the intrinsic catalytic activity of IrO₂ nanoribbon is higher than that of tetragonal phase IrO₂ due to the low d band centre of Ir in this special monoclinic phase structure, as confirmed by density functional theory calculations.Nature communicationsIridium oxide nanoribbons with metastable monoclinic phase for highly efficient electrocatalytic oxygen evolution.PMC99856532017YFA0204800Li YLiao FFan ZShao MJi YZhu WZhong JKang ZShao QYin KfalseIridium oxide nanoribbons with metastable monoclinic phase for highly efficient electrocatalytic oxygen evolution.Metastable metal oxides with ribbon morphologies have promising applications for energy conversion catalysis, however they are largely restricted by their limited synthesis methods. In this study, a monoclinic phase iridium oxide nanoribbon with a space group of C2/m is successfully obtained, which is distinct from rutile iridium oxide with a stable tetragonal phase (P42/mnm). A molten-alkali mechanochemical method provides a unique strategy for achieving this layered nanoribbon structure via a conversion from a monoclinic phase K_0.25IrO₂ (I2/m (12)) precursor. The formation mechanism of IrO₂ nanoribbon is clearly revealed, with its further conversion to IrO₂ nanosheet with a trigonal phase. When applied as an electrocatalyst for the oxygen evolution reaction in acidic condition, the intrinsic catalytic activity of IrO₂ nanoribbon is higher than that of tetragonal phase IrO₂ due to the low d band centre of Ir in this special monoclinic phase structure, as confirmed by density functional theory calculations.2023-01-01T00:00:00Z2023 Mar2026-03-17T15:23:46.402Z2025-02-18T23:35:21.689ZS-EPMC99856533687100210.1038/s41467-023-36833-1