{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1390306495444580352.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.5796/electrochemistry.25-00133"}},{"identifier":{"@type":"URI","@value":"https://www.jstage.jst.go.jp/article/electrochemistry/93/12/93_25-00133/_pdf"}}],"dc:title":[{"@language":"en","@value":"Synthesis of Brownmillerite-type Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub> as a Durable Electrocatalyst for Oxygen Evolution Reaction in Neutral Aqueous Solution"}],"dc:language":"en","description":[{"type":"abstract","notation":[{"@language":"en","@value":"<p>Green hydrogen production and carbon dioxide electroreduction in neutral aqueous solutions, are key reactions for zero-carbon energy systems. In both cases, the oxygen evolution reaction (OER) is a counter reaction that requires a high overpotential. Therefore, active and durable OER catalysts at neutral pH are demanded. We previously reported that brownmillerite-type Ca<sub>2</sub>Fe<sub>0.75</sub>Co<sub>1.25</sub>O<sub>5</sub> calcined at 1073 K exhibits higher OER activity and durability than that of perovskite-type iron cobalt oxides and Ca<sub>2</sub>Fe<sub>2−</sub><i><sub>x</sub></i>Co<i><sub>x</sub></i>O<sub>5</sub> (<i>x</i> ≤ 1) at neutral pH. Here, we synthesized Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub> at temperatures between 1073 and 1373 K and compared its OER activity and durability at neutral pH with those of Ca<sub>2</sub>FeCoO<sub>5</sub> and Ca<sub>2</sub>Fe<sub>0.75</sub>Co<sub>1.25</sub>O<sub>5</sub>. X-ray diffraction and chemical composition analysis revealed that pure brownmillerite phase of Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub> was only achieved at 1273 K, while samples calcined at lower and higher temperatures contained Ca<sub>3</sub>Co<sub>2</sub>O<sub>6</sub> and CaO impurities, respectively. The Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub> exhibited the highest activity and durability for over 100 h, significantly outperforming Ca<sub>2</sub>Fe<sub>0.75</sub>Co<sub>1.25</sub>O<sub>5</sub> without significant changes in morphology or bulk composition.</p>"}],"abstractLicenseFlag":"allow"}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1410306495444580352","@type":"Researcher","personIdentifier":[{"@type":"ORCID","@value":"0000-0001-6723-3165"}],"foaf:name":[{"@language":"en","@value":"OKADA Hiroyuki"}],"jpcoar:affiliationName":[{"@language":"en","@value":"Center for Research on Green Sustainable Chemistry, Tottori University"}]},{"@id":"https://cir.nii.ac.jp/crid/1410306495444580353","@type":"Researcher","personIdentifier":[{"@type":"ORCID","@value":"0000-0002-2783-7017"}],"foaf:name":[{"@language":"en","@value":"TSUJI Etsushi"}],"jpcoar:affiliationName":[{"@language":"en","@value":"Center for Research on Green Sustainable Chemistry, Tottori University"}]},{"@id":"https://cir.nii.ac.jp/crid/1410306495444580354","@type":"Researcher","personIdentifier":[{"@type":"ORCID","@value":"0000-0001-9038-7648"}],"foaf:name":[{"@language":"en","@value":"SUGANUMA Satoshi"}],"jpcoar:affiliationName":[{"@language":"en","@value":"Faculty of Engineering, Hokkaido University"}]},{"@id":"https://cir.nii.ac.jp/crid/1410306495444580355","@type":"Researcher","personIdentifier":[{"@type":"ORCID","@value":"0000-0002-2288-595X"}],"foaf:name":[{"@language":"en","@value":"KATADA Naonobu"}],"jpcoar:affiliationName":[{"@language":"en","@value":"Center for Research on Green Sustainable Chemistry, Tottori University"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"13443542"},{"@type":"LISSN","@value":"13443542"},{"@type":"EISSN","@value":"21862451"}],"prism:publicationName":[{"@language":"en","@value":"Electrochemistry"},{"@language":"en","@value":"Electrochemistry"}],"dc:publisher":[{"@language":"en","@value":"The Electrochemical Society of Japan"},{"@language":"ja","@value":"公益社団法人　電気化学会"}],"prism:publicationDate":"2025-12-09","prism:volume":"93","prism:number":"12","prism:startingPage":"127005","prism:endingPage":"127005"},"reviewed":"false","url":[{"@id":"https://www.jstage.jst.go.jp/article/electrochemistry/93/12/93_25-00133/_pdf"}],"availableAt":"2025-12-09","foaf:topic":[{"@id":"https://cir.nii.ac.jp/all?q=Brownmillerite-type%20Ca%3Csub%3E2%3C/sub%3EFe%3Csub%3E0.5%3C/sub%3ECo%3Csub%3E1.5%3C/sub%3EO%3Csub%3E5%3C/sub%3E","dc:title":"Brownmillerite-type Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub>"},{"@id":"https://cir.nii.ac.jp/all?q=Oxygen%20Evolution%20Reaction","dc:title":"Oxygen Evolution Reaction"},{"@id":"https://cir.nii.ac.jp/all?q=Neutral%20pH","dc:title":"Neutral pH"},{"@id":"https://cir.nii.ac.jp/all?q=Water%20Electrolysis","dc:title":"Water Electrolysis"}],"project":[{"@id":"https://cir.nii.ac.jp/crid/1040018351902384256","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"23K23437"},{"@type":"JGN","@value":"JP23K23437"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23K23437/"}],"notation":[{"@language":"ja","@value":"結晶性複合酸化物の量子ナノ構造体を基軸とした人工光合成助触媒の創製"},{"@language":"en","@value":"Development of Co-catalysts for Artificial Photosynthesis Based on Quantum Nanostructures of Crystalline Solid Solution Oxides"}]},{"@id":"https://cir.nii.ac.jp/crid/1040581456520473088","@type":"Project","projectIdentifier":[{"@type":"KAKEN","@value":"24KJ1706"},{"@type":"JGN","@value":"JP24KJ1706"},{"@type":"URI","@value":"https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-24KJ1706/"}],"notation":[{"@language":"ja","@value":"水電解アノード表面のナノ制御を基にした中性での寿命決定因子の解明と触媒設計"}]},{"@id":"https://cir.nii.ac.jp/crid/1900306495444580352","@type":"Project"},{"@id":"https://cir.nii.ac.jp/crid/1900306495444580355","@type":"Project"}],"relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1050026491351231232","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Influence of Oxide Reservoirs on the Performance of Direct Air Electrolysis Using NaClO4 as a Deliquescent Neutral Electrolyte Salt"},{"@value":"Influence of Oxide Reservoirs on the Performance of Direct Air Electrolysis Using NaClO<sub>4</sub> as a Deliquescent Neutral Electrolyte Salt"}]},{"@id":"https://cir.nii.ac.jp/crid/1050306506451394560","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Highly Durable Oxygen Evolution Reaction Catalyst: Amorphous Oxyhydroxide Derived from Brownmillerite-Type Ca2FeCoO5"},{"@value":"Highly Durable Oxygen Evolution Reaction Catalyst: Amorphous Oxyhydroxide Derived from Brownmillerite-Type Ca<sub>2</sub>FeCoO<sub>5</sub>"}]},{"@id":"https://cir.nii.ac.jp/crid/1360009142482107648","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Water Electrolysis in Saturated Phosphate Buffer at Neutral pH"}]},{"@id":"https://cir.nii.ac.jp/crid/1360011144790636672","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Photoelectrocatalytic reduction of carbon dioxide in aqueous suspensions of semiconductor powders"}]},{"@id":"https://cir.nii.ac.jp/crid/1360011145739935360","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Brownmillerite‐type Ca<sub>2</sub>FeCoO<sub>5</sub> as a Practicable Oxygen Evolution Reaction Catalyst"}]},{"@id":"https://cir.nii.ac.jp/crid/1360025029351165312","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Metal‐Free N, P‐Codoped Carbon for Syngas Production with Tunable Composition via CO<sub>2</sub> Electrolysis: Addressing the Competition Between CO<sub>2</sub> Reduction and H<sub>2</sub> Evolution"}]},{"@id":"https://cir.nii.ac.jp/crid/1360025029618473088","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Brownmillerite-Type Ca<sub>2</sub>FeCoO<sub>5</sub> Ultrathin Layers as Anodic Catalysts for Water Electrolysis"}]},{"@id":"https://cir.nii.ac.jp/crid/1360025031893937152","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Origin of Ising magnetism in Ca3Co2O6 unveiled by orbital imaging"}]},{"@id":"https://cir.nii.ac.jp/crid/1360025034121220480","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Enhancing the Activity and Stability of IrO<sub>2</sub> for the Oxygen Evolution Reaction over a Wide pH Range using Electrodeposited BaO<sub>2</sub>"}]},{"@id":"https://cir.nii.ac.jp/crid/1360286989819393920","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Brownmillerite‐Type Crystalline Ca<sub>2</sub>FeCoO<sub>5</sub> Ultrasmall Particles with Single‐Nanometer Dimensions as an Active Cocatalyst for Oxygen Photoevolution Reaction"}]},{"@id":"https://cir.nii.ac.jp/crid/1360298342333236224","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"High Spin State Promotes Water Oxidation Catalysis at Neutral pH in Spinel Cobalt Oxide"}]},{"@id":"https://cir.nii.ac.jp/crid/1360298345069298176","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Improvement of Photoelectrocatalytic Activity and Stability of WO<sub>3</sub> for Oxygen Photoevolution Reaction by Loading of Brownmillerite‐Type Ca<sub>2</sub>FeCoO<sub>5</sub> as a Cocatalyst"}]},{"@id":"https://cir.nii.ac.jp/crid/1360298754827176192","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Ultra-high-rate CO\n                    <sub>2</sub>\n                    reduction reactions to multicarbon products with a current density of 1.7 A cm\n                    <sup>−2</sup>\n                    in neutral electrolytes"}]},{"@id":"https://cir.nii.ac.jp/crid/1360298755642080256","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Brownmillerite-type Ca<sub>2</sub>Fe<sub>0.75</sub>Co<sub>1.25</sub>O<sub>5</sub> as a robust electrocatalyst for the oxygen evolution reaction under neutral conditions"}]},{"@id":"https://cir.nii.ac.jp/crid/1360306504212007808","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Thermodynamic modeling of the Sr–Co–Fe–O system"}]},{"@id":"https://cir.nii.ac.jp/crid/1360306507964379776","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Negative chemical pressure effects induced by Y substitution for Ca on the ‘exotic’ magnetic behavior of the spin-chain compound, Ca3Co2O6"}]},{"@id":"https://cir.nii.ac.jp/crid/1360574093726869632","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water"}]},{"@id":"https://cir.nii.ac.jp/crid/1360574094565314176","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Electronic Design Criteria for O−O Bond Formation via Metal−Oxo Complexes"}]},{"@id":"https://cir.nii.ac.jp/crid/1360574095742292480","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Advancing the Electrochemistry of the Hydrogen‐Evolution Reaction through Combining Experiment and Theory"}]},{"@id":"https://cir.nii.ac.jp/crid/1360580235596011392","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Co3O4 Nanorods—Efficient Non-noble Metal Electrocatalyst for Oxygen Evolution at Neutral pH"}]},{"@id":"https://cir.nii.ac.jp/crid/1360580235959324672","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Oxygen evolution reaction activity and underlying mechanism of perovskite electrocatalysts at different pH"}]},{"@id":"https://cir.nii.ac.jp/crid/1360580237155198208","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Transition metal based heterogeneous electrocatalysts for the oxygen evolution reaction at near-neutral pH"}]},{"@id":"https://cir.nii.ac.jp/crid/1360587980848046208","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Preparation and characterization of Ca3Co2O6 as cathode for intermediate temperature solid oxide fuel cells"}]},{"@id":"https://cir.nii.ac.jp/crid/1360587981671100416","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Impedance of porous electrodes"}]},{"@id":"https://cir.nii.ac.jp/crid/1360587983091383936","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Enhanced electrochemical activity in Ca3Co2O6 cathode for solid-oxide fuel cells by Cu substitution"}]},{"@id":"https://cir.nii.ac.jp/crid/1360846640837043712","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Electrocatalytic activity of amorphous RuO2 electrode for oxygen evolution in an aqueous solution"}]},{"@id":"https://cir.nii.ac.jp/crid/1360846641734734976","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Covalency-reinforced oxygen evolution reaction catalyst"}]},{"@id":"https://cir.nii.ac.jp/crid/1360855569492654208","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Activating lattice oxygen redox reactions in metal oxides to catalyse oxygen evolution"}]},{"@id":"https://cir.nii.ac.jp/crid/1360869456021135232","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Structural phase stability and magnetism in Co2FeO4 spinel oxide"}]},{"@id":"https://cir.nii.ac.jp/crid/1361418520342430208","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Bifunctional Oxygen Reduction and Evolution Activity in Brownmillerites Ca<sub>2</sub>Fe<sub>(1–<i>x</i>)</sub>Co<sub><i>x</i></sub>O<sub>5</sub>"}]},{"@id":"https://cir.nii.ac.jp/crid/1361418520370913664","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"An Iron-based Film for Highly Efficient Electrocatalytic Oxygen Evolution from Neutral Aqueous Solution"}]},{"@id":"https://cir.nii.ac.jp/crid/1361699994738605568","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"High-Index Faceted Ni<sub>3</sub>S<sub>2</sub> Nanosheet Arrays as Highly Active and Ultrastable Electrocatalysts for Water Splitting"}]},{"@id":"https://cir.nii.ac.jp/crid/1361975842828872320","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Transition-Metal Distribution in Brownmillerite Ca<sub>2</sub>FeCoO<sub>5</sub>"}]},{"@id":"https://cir.nii.ac.jp/crid/1361981468626970624","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Electrochemical Photolysis of Water at a Semiconductor Electrode"}]},{"@id":"https://cir.nii.ac.jp/crid/1361981468966148608","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Activity and stability trends of perovskite oxides for oxygen evolution catalysis at neutral pH"}]},{"@id":"https://cir.nii.ac.jp/crid/1362544421021582080","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"A Perovskite Oxide Optimized for Oxygen Evolution Catalysis from Molecular Orbital Principles"}]},{"@id":"https://cir.nii.ac.jp/crid/1362825893892741120","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Activation of Catalytically Active Edge-Sharing Domains in Ca<sub>2</sub>FeCoO<sub>5</sub> for Oxygen Evolution Reaction in Highly Alkaline Media"}]},{"@id":"https://cir.nii.ac.jp/crid/1363670318495288192","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Tailoring the Co 3d-O 2p Covalency in LaCoO<sub>3</sub> by Fe Substitution To Promote Oxygen Evolution Reaction"}]},{"@id":"https://cir.nii.ac.jp/crid/1363951795923186944","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"A large-sized cell for solar-driven CO2 conversion with a solar-to-formate conversion efficiency of 7.2%"}]},{"@id":"https://cir.nii.ac.jp/crid/1364233270866727936","@type":"Article","relationType":["references"],"jpcoar:relatedTitle":[{"@value":"Solar conversion of CO2 to CO using Earth-abundant electrocatalysts prepared by atomic layer modification of CuO"}]},{"@id":"https://cir.nii.ac.jp/crid/1460024965220033664","@type":"Dataset","resourceType":"データセット(Dataset)","relationType":["references"],"jpcoar:relatedTitle":[{"@language":"en","@value":"Synthesis of Brownmillerite-type Ca<sub>2</sub>Fe<sub>0.5</sub>Co<sub>1.5</sub>O<sub>5</sub> as a Durable Electrocatalyst for Oxygen Evolution Reaction in Neutral Aqueous Solution (Supporting Information)"}]}],"dataSourceIdentifier":[{"@type":"JALC","@value":"oai:japanlinkcenter.org:2014842581"},{"@type":"CROSSREF","@value":"10.5796/electrochemistry.25-00133"},{"@type":"JALC","@value":"oai:japanlinkcenter.org:2014701060_isReferencedBy_DOI_Lu3YpBdyORzGUfavxVmM0Kkpfb3"},{"@type":"JALC","@value":"oai:japanlinkcenter.org:2014701059_isReferencedBy_DOI_Lu3YpBdyORzGUfavxVmM0Kkpfb3"}]}