Mn3O4@CoMn2O4–CoxOy Nanoparticles: Partial Cation Exchange Synthesis and Electrocatalytic Properties toward the Oxygen Reduction and Evolution Reactions

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• 作者：Zhishan Luo ; Erdem Irtem ; Maria Ibáñez ; Raquel Nafria ; Sara Martı́-Sánchez ; Aziz Genç ; Maria de la Mata ; Yu Liu ; Doris Cadavid ; Jordi Llorca ; Jordi Arbiol ; Teresa Andreu ; Joan Ramon Morante ; Andreu Cabot
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：8
• 期：27
• 页码：17435-17444
• 全文大小：759K
• 年卷期：0
• ISSN：1944-8252

文摘

Mn₃O₄@CoMn₂O₄ nanoparticles (NPs) were produced at low temperature and ambient atmosphere using a one-pot two-step synthesis protocol involving the cation exchange of Mn by Co in preformed Mn₃O₄ NPs. Selecting the proper cobalt precursor, the nucleation of Co_xO_y crystallites at the Mn₃O₄@CoMn₂O₄ surface could be simultaneously promoted to form Mn₃O₄@CoMn₂O₄–Co_xO_y NPs. Such heterostructured NPs were investigated for oxygen reduction and evolution reactions (ORR, OER) in alkaline solution. Mn₃O₄@CoMn₂O₄–Co_xO_y NPs with [Co]/[Mn] = 1 showed low overpotentials of 0.31 V at −3 mA·cm^–2 and a small Tafel slope of 52 mV·dec^–1 for ORR, and overpotentials of 0.31 V at 10 mA·cm^–2 and a Tafel slope of 81 mV·dec^–1 for OER, thus outperforming commercial Pt-, IrO₂-based and previously reported transition metal oxides. This cation-exchange-based synthesis protocol opens up a new approach to design novel heterostructured NPs as efficient nonprecious metal bifunctional oxygen catalysts.