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Neutral water oxidation is a crucial half‐reaction for various electrochemical applications requiring pH‐benign conditions. However, its sluggish kinetics with limited proton and electron transfer rates greatly impacts the overall energy efficiency. In this work, we created an electrode/electrolyte synergy strategy for simultaneously enhancing the proton and electron transfers at the interface toward highly efficient neutral water oxidation. The charge transfer was accelerated between the iridium oxide and in situ formed nickel oxyhydroxide on the electrode end. The proton transfer was expedited by the compact borate environment that originated from hierarchical fluoride/borate anions on the electrolyte end. These concerted promotions facilitated the proton‐coupled electron transfer (PCET) events. Due to the electrode/electrolyte synergy, Ir−O and Ir−OO− intermediates could be directly detected by in situ Raman spectroscopy, and the rate‐limiting step of Ir−O oxidation was determined. This synergy strategy can extend the scope of optimizing electrocatalytic activities toward more electrode/electrolyte combinations. [ABSTRACT FROM AUTHOR]

Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO2 nanosheets in a family of charge‐ordered La1−xAExMnO3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn3+ and bond‐strength differences. ϵ‐MnO2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures. [ABSTRACT FROM AUTHOR]

Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO2 nanosheets in a family of charge‐ordered La1−xAExMnO3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn3+ and bond‐strength differences. ϵ‐MnO2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures. [ABSTRACT FROM AUTHOR]

Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO2 nanosheets in a family of charge‐ordered La1−xAExMnO3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn3+ and bond‐strength differences. ϵ‐MnO2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures. [ABSTRACT FROM AUTHOR]

Exfoliation of non‐layered (structurally) bulk materials at the nanoscale is challenging because of the strong chemical bonds in the lattice, as opposed to the weak van der Waals (vdW) interactions in layered materials. We propose a top‐down method to exfoliate ϵ‐MnO2 nanosheets in a family of charge‐ordered La1−xAExMnO3 (AE=Ca, Sr, Ba) perovskites, taking advantage of the Jahn–Teller disproportionation effect of Mn3+ and bond‐strength differences. ϵ‐MnO2 crystallized into a nickel arsenide (NiAs) structure, with a thickness of 0.91 nm, displays thermal metastability and superior water oxidation activity compared to other manganese oxides. The exfoliation mechanism involves a synergistic proton‐induced Mn3+ disproportionation and structural reconstruction. The synthetic method could also be potentially extended to the exfoliation of other two‐dimensional nanosheet materials with non‐layered structures. [ABSTRACT FROM AUTHOR]