Boosting Water Oxidation through In Situ Electroconversion of Manganese Gallide: An Intermetallic Precursor Approach |
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Authors: | Prashanth W Menezes Carsten Walter Jan Niklas Hausmann Rodrigo Beltrn‐Suito Christopher Schlesiger Sebastian Praetz Valeriy Yu Verchenko Andrei V Shevelkov Matthias Driess |
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Institution: | Prashanth W. Menezes,Carsten Walter,Jan Niklas Hausmann,Rodrigo Beltrán‐Suito,Christopher Schlesiger,Sebastian Praetz,Valeriy Yu. Verchenko,Andrei V. Shevelkov,Matthias Driess |
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Abstract: | For the first time, the manganese gallide (MnGa4) served as an intermetallic precursor, which upon in situ electroconversion in alkaline media produced high‐performance and long‐term‐stable MnOx‐based electrocatalysts for water oxidation. Unexpectedly, its electrocorrosion (with the concomitant loss of Ga) leads simultaneously to three crystalline types of MnOx minerals with distinct structures and induced defects: birnessite δ‐MnO2, feitknechtite β‐MnOOH, and hausmannite α‐Mn3O4. The abundance and intrinsic stabilization of MnIII/MnIV active sites in the three MnOx phases explains the superior efficiency and durability of the system for electrocatalytic water oxidation. After electrophoretic deposition of the MnGa4 precursor on conductive nickel foam (NF), a low overpotential of 291 mV, comparable to that of precious‐metal‐based catalysts, could be achieved at a current density of 10 mA cm?2 with a durability of more than five days. |
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Keywords: | electrocorrosion MnOx minerals oxygen evolution reaction renewable energy water-splitting electrocatalysts |
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