Evaporated manganese films as a starting point for the preparation of thin-layer MnOx water-oxidation anodes. Issue 5 (15th May 2017)

• Record Type: Journal Article
• Authors: Frey, Carolin E.; Kwok, Frances; Gonzáles-Flores, Diego; Ohms, Jonas; Cooley, Kayla A.; Dau, Holger; Zaharieva, Ivelina; Walter, Timothy N.; Simchi, Hamed; Mohney, Suzanne E.; Kurz, Philipp
• Is Part Of: Sustainable energy & fuels. Volume 1:Issue 5(2017)
• Page Start: 1162
• Page End: 1170
• Publication Date: 2017-05-15
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/c7se00172j
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : Physical vapour deposition of Mn metal followed by annealing in air is a promising route to prepare MnO x -anodes for water-oxidation. Abstract : A novel method to prepare anodes for water electrolysis cells has been developed, which starts from layers of elemental manganese deposited by physical vapour deposition (PVD) on indium-doped tin oxide (ITO). Oxidation in dry air at 300 °C transforms this metallic Mn layer into a manganese(ii )-rich MnO x coating ( x = 1–1.3), which also contains a buried layer of an In–Sn alloy originating from reactions with the ITO support. The MnO x films are well connected to the underlying substrate and act as efficient catalysts for water-oxidation catalysis (WOC) at neutral pH. Detailed post-operando analyses using XRD, SEM, TEM and XAS revealed that the dense MnO/Mn3 O4 film is virtually not affected by 2 h of electrochemical WOC at E ≈ +1.8 V vs. RHE, corresponding well to the observed good stability of catalytic currents, which is unusual for such thin layers of a MnO x catalyst. The current densities during electrolyses are so far low ( i ≈ 50–100 μA cm −2 at pH 7), but optimization of the preparation process may allow for significant improvements. This new, rather easy, and adaptable preparation method for stable, thin-layer MnO x water-oxidation anodes could thus prove to be very useful for a variety of applications.